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Literature & Frontiers
  • 1 Richard J. Pierce, Chevron and Its Aftermath, 41 Vand. L. Rev. 301 (1988)

  • 2 Antonin Scalia, Judicial Deference to Administrative Interpretations of Law, 1989 Duke L. J. 511

  • 3 Thomas W. Merrill, Judicial Deference to Executive Precedent, 101 Yale L.J. 969 (1992)

  • 4 Ackerman & Heinzerling, Pricing the Priceless

  • 5 Gonzales v. Oregon

    1

    546 U.S. 243 (2006)

    2
    GONZALES, ATTORNEY GENERAL, ET AL.
    v.
    OREGON ET AL.

    No. 04-623.

    3

    Supreme Court of United States.

    Argued October 5, 2005.
    Decided January 17, 2006.

    4

    [247] Solicitor General Clement argued the cause for petitioners. With him on the briefs were Assistant Attorney General Keisler, Deputy Solicitor General Kneedler, Deputy Assistant Attorney General Katsas, Douglas Hallward-Driemeier, Mark B. Stern, and Jonathan H. Levy.

    5

    Robert M. Atkinson, Senior Assistant Attorney General of Oregon, argued the cause for respondents. With him on the brief for respondent State of Oregon were Hardy Myers, Attorney General, Peter Shepherd, Deputy Attorney General, and Mary H. Williams, Solicitor General. Nicholas W. van Aelstyn, Aaron S. Jacobs, and Kathryn L. Tucker filed a brief for Patient-Respondents. Eli D. Stutsman filed a brief for respondents Peter A. Rasmussen, M. D., et al.[1]

    6
    [248] JUSTICE KENNEDY delivered the opinion of the Court.
    7

    The question before us is whether the Controlled Substances Act allows the United States Attorney General to [249] prohibit doctors from prescribing regulated drugs for use in physician-assisted suicide, notwithstanding a state law permitting the procedure. As the Court has observed, "Americans are engaged in an earnest and profound debate about the morality, legality, and practicality of physician-assisted suicide." Washington v. Glucksberg, 521 U.S. 702, 735 (1997). The dispute before us is in part a product of this political and moral debate, but its resolution requires an inquiry familiar to the courts: interpreting a federal statute to determine whether executive action is authorized by, or otherwise consistent with, the enactment.

    8

    In 1994, Oregon became the first State to legalize assisted suicide when voters approved a ballot measure enacting the Oregon Death With Dignity Act (ODWDA). Ore. Rev. Stat. § 127.800 et seq. (2003). ODWDA, which survived a 1997 ballot measure seeking its repeal, exempts from civil or criminal liability state-licensed physicians who, in compliance with the specific safeguards in ODWDA, dispense or prescribe a lethal dose of drugs upon the request of a terminally ill patient.

    9

    The drugs Oregon physicians prescribe under ODWDA are regulated under a federal statute, the Controlled Substances Act (CSA or Act). 84 Stat. 1242, as amended, 21 U.S.C. § 801 et seq. The CSA allows these particular drugs to be available only by a written prescription from a registered physician. In the ordinary course the same drugs are prescribed in smaller doses for pain alleviation.

    10

    A November 9, 2001, Interpretive Rule issued by the Attorney General addresses the implementation and enforcement of the CSA with respect to ODWDA. It determines that using controlled substances to assist suicide is not a legitimate medical practice and that dispensing or prescribing them for this purpose is unlawful under the CSA. The Interpretive Rule's validity under the CSA is the issue before us.

    11
    [250] I
    12
    A
    13

    We turn first to the text and structure of the CSA. Enacted in 1970 with the main objectives of combating drug abuse and controlling the legitimate and illegitimate traffic in controlled substances, the CSA creates a comprehensive, closed regulatory regime criminalizing the unauthorized manufacture, distribution, dispensing, and possession of substances classified in any of the Act's five schedules. Gonzales v. Raich, 545 U.S. 1, 12-13 (2005); 21 U.S.C. § 841 (2000 ed. and Supp. II); 21 U.S.C. § 844. The Act places substances in one of five schedules based on their potential for abuse or dependence, their accepted medical use, and their accepted safety for use under medical supervision. Schedule I contains the most severe restrictions on access and use, and Schedule V the least. Raich, supra, at 14; 21 U.S.C. § 812. Congress classified a host of substances when it enacted the CSA, but the statute permits the Attorney General to add, remove, or reschedule substances. He may do so, however, only after making particular findings, and on scientific and medical matters he is required to accept the findings of the Secretary of Health and Human Services (Secretary). These proceedings must be on the record after an opportunity for comment. See 21 U.S.C. § 811 (2000 ed. and Supp. V).

    14

    The present dispute involves controlled substances listed in Schedule II, substances generally available only pursuant to a written, nonrefillable prescription by a physician. 21 U.S.C. § 829(a). A 1971 regulation promulgated by the Attorney General requires that every prescription for a controlled substance "be issued for a legitimate medical purpose by an individual practitioner acting in the usual course of his professional practice." 21 CFR § 1306.04(a) (2005).

    15

    To prevent diversion of controlled substances with medical uses, the CSA regulates the activity of physicians. To issue [251] lawful prescriptions of Schedule II drugs, physicians must "obtain from the Attorney General a registration issued in accordance with the rules and regulations promulgated by him." 21 U.S.C. § 822(a)(2). The Attorney General may deny, suspend, or revoke this registration if, as relevant here, the physician's registration would be "inconsistent with the public interest." § 824(a)(4); § 822(a)(2). When deciding whether a practitioner's registration is in the public interest, the Attorney General "shall" consider:

    16

    "(1) The recommendation of the appropriate State licensing board or professional disciplinary authority.

    "(2) The applicant's experience in dispensing, or conducting research with respect to controlled substances.

    "(3) The applicant's conviction record under Federal or State laws relating to the manufacture, distribution, or dispensing of controlled substances.

    "(4) Compliance with applicable State, Federal, or local laws relating to controlled substances.

    "(5) Such other conduct which may threaten the public health and safety." § 823(f).

    17

    The CSA explicitly contemplates a role for the States in regulating controlled substances, as evidenced by its pre-emption provision.

    18

    "No provision of this subchapter shall be construed as indicating an intent on the part of the Congress to occupy the field in which that provision operates . . . to the exclusion of any State law on the same subject matter which would otherwise be within the authority of the State, unless there is a positive conflict between that provision . . . and that State law so that the two cannot consistently stand together." § 903.

    19
    B
    20

    Oregon voters enacted ODWDA in 1994. For Oregon residents to be eligible to request a prescription under [252] ODWDA, they must receive a diagnosis from their attending physician that they have an incurable and irreversible disease that, within reasonable medical judgment, will cause death within six months. Ore. Rev. Stat. §§ 127.815, 127.800(12) (2003). Attending physicians must also determine whether a patient has made a voluntary request, ensure a patient's choice is informed, and refer patients to counseling if they might be suffering from a psychological disorder or depression causing impaired judgment. §§ 127.815, 127.825. A second "consulting" physician must examine the patient and the medical record and confirm the attending physician's conclusions. § 127.800(8). Oregon physicians may dispense or issue a prescription for the requested drug, but may not administer it. §§ 127.815(1)(L), 127.880.

    21

    The reviewing physicians must keep detailed medical records of the process leading to the final prescription, § 127.855, records that Oregon's Department of Human Services reviews, § 127.865. Physicians who dispense medication pursuant to ODWDA must also be registered with both the State's Board of Medical Examiners and the federal Drug Enforcement Administration (DEA). § 127.815(1)(L). In 2004, 37 patients ended their lives by ingesting a lethal dose of medication prescribed under ODWDA. Oregon Dept. of Human Servs., Seventh Annual Report on Oregon's Death with Dignity Act 20 (Mar. 10, 2005).

    22
    C
    23

    In 1997, Members of Congress concerned about ODWDA invited the DEA to prosecute or revoke the CSA registration of Oregon physicians who assist suicide. They contended that hastening a patient's death is not legitimate medical practice, so prescribing controlled substances for that purpose violates the CSA. Letter from Sen. Orrin Hatch and Rep. Henry Hyde to Thomas A. Constantine (July 25, 1997), reprinted in Hearing on S. 2151 before the Senate Committee on the Judiciary, 105th Cong., 2d Sess., 2-3 (1999) [253] (hereinafter Hearing). The letter received an initial, favorable response from the director of the DEA, see Letter from Thomas A. Constantine to Sen. Orrin Hatch (Nov. 5, 1997), Hearing 4-5, but Attorney General Reno considered the matter and concluded that the DEA could not take the proposed action because the CSA did not authorize it to "displace the states as the primary regulators of the medical profession, or to override a state's determination as to what constitutes legitimate medical practice," Letter from Attorney General Janet Reno to Sen. Orrin Hatch, on Oregon's Death with Dignity Act (June 5, 1998), Hearing 5-6. Legislation was then introduced to grant the explicit authority Attorney General Reno found lacking; but it failed to pass. See H. R. 4006, 105th Cong., 2d Sess. (1998); H. R. 2260, 106th Cong., 1st Sess. (1999).

    24

    In 2001, John Ashcroft was appointed Attorney General. Perhaps because Mr. Ashcroft had supported efforts to curtail assisted suicide while serving as a Senator, see, e. g., 143 Cong. Rec. 5589-5590 (1997) (remarks of Sen. Ashcroft), Oregon Attorney General Hardy Myers wrote him to request a meeting with Department of Justice officials should the Department decide to revisit the application of the CSA to assisted suicide. Letter of Feb. 2, 2001, App. to Brief for Patient-Respondents in Opposition 55a. Attorney General Myers received a reply letter from one of Attorney General Ashcroft's advisers writing on his behalf, which stated:

    25

    "I am aware of no pending legislation in Congress that would prompt a review of the Department's interpretation of the CSA as it relates to physician-assisted suicide. Should such a review be commenced in the future, we would be happy to include your views in that review." Letter from Lori Sharpe (Apr. 17, 2001), id., at 58a.

    26

    On November 9, 2001, without consulting Oregon or apparently anyone outside his Department, the Attorney General [254] issued an Interpretive Rule announcing his intent to restrict the use of controlled substances for physician-assisted suicide. Incorporating the legal analysis of a memorandum he had solicited from his Office of Legal Counsel, the Attorney General ruled:

    27

    "[A]ssisting suicide is not a `legitimate medical purpose' within the meaning of 21 CFR 1306.04 (2001), and that prescribing, dispensing, or administering federally controlled substances to assist suicide violates the Controlled Substances Act. Such conduct by a physician registered to dispense controlled substances may `render his registration . . . inconsistent with the public interest' and therefore subject to possible suspension or revocation under 21 U.S.C. 824(a)(4). The Attorney General's conclusion applies regardless of whether state law authorizes or permits such conduct by practitioners or others and regardless of the condition of the person whose suicide is assisted." 66 Fed. Reg. 56608 (2001).

    28

    There is little dispute that the Interpretive Rule would substantially disrupt the ODWDA regime. Respondents contend, and petitioners do not dispute, that every prescription filled under ODWDA has specified drugs classified under Schedule II. A physician cannot prescribe the substances without DEA registration, and revocation or suspension of the registration would be a severe restriction on medical practice. Dispensing controlled substances without a valid prescription, furthermore, is a federal crime. See, e. g., 21 U.S.C. § 841(a)(1); United States v. Moore, 423 U.S. 122 (1975).

    29

    In response the State of Oregon, joined by a physician, a pharmacist, and some terminally ill patients, all from Oregon, challenged the Interpretive Rule in federal court. The United States District Court for the District of Oregon entered a permanent injunction against the Interpretive Rule's enforcement.

    30

    [255] A divided panel of the Court of Appeals for the Ninth Circuit granted the petitions for review and held the Interpretive Rule invalid. Oregon v. Ashcroft, 368 F.3d 1118 (2004). It reasoned that, by making a medical procedure authorized under Oregon law a federal offense, the Interpretive Rule altered the "`"usual constitutional balance between the States and the Federal Government"'" without the requisite clear statement that the CSA authorized such action. Id., at 1124-1125 (quoting Gregory v. Ashcroft, 501 U.S. 452, 460 (1991), in turn quoting Atascadero State Hospital v. Scanlon, 473 U.S. 234, 242 (1985)). The Court of Appeals held in the alternative that the Interpretive Rule could not be squared with the plain language of the CSA, which targets only conventional drug abuse and excludes the Attorney General from decisions on medical policy. 368 F.3d, at 1125-1129.

    31

    We granted the Government's petition for certiorari. 543 U.S. 1145 (2005).

    32
    II
    33

    Executive actors often must interpret the enactments Congress has charged them with enforcing and implementing. The parties before us are in sharp disagreement both as to the degree of deference we must accord the Interpretive Rule's substantive conclusions and whether the Rule is authorized by the statutory text at all. Although balancing the necessary respect for an agency's knowledge, expertise, and constitutional office with the courts' role as interpreter of laws can be a delicate matter, familiar principles guide us. An administrative rule may receive substantial deference if it interprets the issuing agency's own ambiguous regulation. Auer v. Robbins, 519 U.S. 452, 461-463 (1997). An interpretation of an ambiguous statute may also receive substantial deference. Chevron U.S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 842-845 (1984). Deference in accordance with Chevron, however, is warranted only "when it appears that Congress delegated authority to the agency generally to make rules carrying the force of law, [256] and that the agency interpretation claiming deference was promulgated in the exercise of that authority." United States v. Mead Corp., 533 U.S. 218, 226-227 (2001). Otherwise, the interpretation is "entitled to respect" only to the extent it has the "power to persuade." Skidmore v. Swift & Co., 323 U.S. 134, 140 (1944).

    34
    A
    35

    The Government first argues that the Interpretive Rule is an elaboration of one of the Attorney General's own regulations, 21 CFR § 1306.04 (2005), which requires all prescriptions be issued "for a legitimate medical purpose by an individual practitioner acting in the usual course of his professional practice." As such, the Government says, the Interpretive Rule is entitled to considerable deference in accordance with Auer.

    36

    In our view Auer and the standard of deference it accords to an agency are inapplicable here. Auer involved a disputed interpretation of the Fair Labor Standards Act of 1938 as applied to a class of law enforcement officers. Under regulations promulgated by the Secretary of Labor, an exemption from overtime pay depended, in part, on whether the employees met the "salary basis" test. 519 U.S., at 454-455. In this Court the Secretary of Labor filed an amicus brief explaining why, in his view, the regulations gave exempt status to the officers. Id., at 461. We gave weight to that interpretation, holding that because the applicable test was "a creature of the Secretary's own regulations, his interpretation of it is, under our jurisprudence, controlling unless plainly erroneous or inconsistent with the regulation." Ibid. (internal quotation marks omitted).

    37

    In Auer, the underlying regulations gave specificity to a statutory scheme the Secretary of Labor was charged with enforcing and reflected the considerable experience and expertise the Department of Labor had acquired over time with respect to the complexities of the Fair Labor Standards [257] Act. Here, on the other hand, the underlying regulation does little more than restate the terms of the statute itself. The language the Interpretive Rule addresses comes from Congress, not the Attorney General, and the near equivalence of the statute and regulation belies the Government's argument for Auer deference.

    38

    The Government does not suggest that its interpretation turns on any difference between the statutory and regulatory language. The CSA allows prescription of drugs only if they have a "currently accepted medical use," 21 U.S.C. § 812(b); requires a "medical purpose" for dispensing the least controlled substances of those on the schedules, § 829(c); and, in its reporting provision, defines a "valid prescription" as one "issued for a legitimate medical purpose," § 830(b)(3)(A)(ii). Similarly, physicians are considered to be acting as practitioners under the statute if they dispense controlled substances "in the course of professional practice." § 802(21). The regulation uses the terms "legitimate medical purpose" and "the course of professional practice," ibid., but this just repeats two statutory phrases and attempts to summarize the others. It gives little or no instruction on a central issue in this case: Who decides whether a particular activity is in "the course of professional practice" or done for a "legitimate medical purpose"? Since the regulation gives no indication how to decide this issue, the Attorney General's effort to decide it now cannot be considered an interpretation of the regulation. Simply put, the existence of a parroting regulation does not change the fact that the question here is not the meaning of the regulation but the meaning of the statute. An agency does not acquire special authority to interpret its own words when, instead of using its expertise and experience to formulate a regulation, it has elected merely to paraphrase the statutory language.

    39

    Furthermore, as explained below, if there is statutory authority to issue the Interpretive Rule it comes from the 1984 amendments to the CSA that gave the Attorney General authority [258] to register and deregister physicians based on the public interest. The regulation was enacted before those amendments, so the Interpretive Rule cannot be justified as indicative of some intent the Attorney General had in 1971. That the current interpretation runs counter to the "intent at the time of the regulation's promulgation" is an additional reason why Auer deference is unwarranted. Thomas Jefferson Univ. v. Shalala, 512 U.S. 504, 512 (1994) (internal quotation marks omitted). Deference under Auer being inappropriate, we turn to the question whether the Interpretive Rule, on its own terms, is a permissible interpretation of the CSA.

    40
    B
    41

    Just as the Interpretive Rule receives no deference under Auer, neither does it receive deference under Chevron. If a statute is ambiguous, judicial review of administrative rulemaking often demands Chevron deference; and the rule is judged accordingly. All would agree, we should think, that the statutory phrase "legitimate medical purpose" is a generality, susceptible to more precise definition and open to varying constructions, and thus ambiguous in the relevant sense. Chevron deference, however, is not accorded merely because the statute is ambiguous and an administrative official is involved. To begin with, the rule must be promulgated pursuant to authority Congress has delegated to the official. Mead, supra, at 226-227.

    42

    The Attorney General has rulemaking power to fulfill his duties under the CSA. The specific respects in which he is authorized to make rules, however, instruct us that he is not authorized to make a rule declaring illegitimate a medical standard for care and treatment of patients that is specifically authorized under state law.

    43

    The starting point for this inquiry is, of course, the language of the delegation provision itself. In many cases authority is clear because the statute gives an agency broad power to enforce all provisions of the statute. See, e. g., National [259] Cable & Telecommunications Assn. v. Brand X Internet Services, 545 U.S. 967, 980 (2005) (explaining that a Federal Communications Commission regulation received Chevron deference because "Congress has delegated to the Commission the authority to . . . `prescribe such rules and regulations as may be necessary in the public interest to carry out the provisions' of the Act" (quoting 47 U.S.C. § 201(b))); Household Credit Services, Inc. v. Pfennig, 541 U.S. 232, 238 (2004) (giving Chevron deference to a Federal Reserve Board regulation where "Congress has expressly delegated to the Board the authority to prescribe regulations. . . as, in the judgment of the Board, `are necessary or proper to effectuate the purposes of'" the statute (quoting 15 U.S.C. § 1604(a))). The CSA does not grant the Attorney General this broad authority to promulgate rules.

    44

    The CSA gives the Attorney General limited powers, to be exercised in specific ways. His rulemaking authority under the CSA is described in two provisions: (1) "The Attorney General is authorized to promulgate rules and regulations and to charge reasonable fees relating to the registration and control of the manufacture, distribution, and dispensing of controlled substances and to listed chemicals," 21 U.S.C. § 821 (2000 ed., Supp. V); and (2) "The Attorney General may promulgate and enforce any rules, regulations, and procedures which he may deem necessary and appropriate for the efficient execution of his functions under this subchapter," 21 U.S.C. § 871(b). As is evident from these sections, Congress did not delegate to the Attorney General authority to carry out or effect all provisions of the CSA. Rather, he can promulgate rules relating only to "registration" and "control," and "for the efficient execution of his functions" under the statute.

    45

    Turning first to the Attorney General's authority to make regulations for the "control" of drugs, this delegation cannot sustain the Interpretive Rule's attempt to define standards of medical practice. Control is a term of art in the CSA. [260] "As used in this subchapter," § 802—the subchapter that includes § 821—

    46

    "The term `control' means to add a drug or other substance, or immediate precursor, to a schedule under part B of this subchapter, whether by transfer from another schedule or otherwise." § 802(5).

    47

    To exercise his scheduling power, the Attorney General must follow a detailed set of procedures, including requesting a scientific and medical evaluation from the Secretary. See 21 U.S.C. §§ 811, 812 (2000 ed. and Supp. V). The statute is also specific as to the manner in which the Attorney General must exercise this authority: "Rules of the Attorney General under this subsection [regarding scheduling] shall be made on the record after opportunity for a hearing pursuant to the rulemaking procedures prescribed by [the Administrative Procedure Act, 5 U.S.C. § 553]." 21 U.S.C. § 811(a). The Interpretive Rule now under consideration does not concern the scheduling of substances and was not issued after the required procedures for rules regarding scheduling, so it cannot fall under the Attorney General's "control" authority.

    48

    Even if "control" in § 821 were understood to signify something other than its statutory definition, it would not support the Interpretive Rule. The statutory references to "control" outside the scheduling context make clear that the Attorney General can establish controls "against diversion," e. g., § 823(a)(1), but do not give him authority to define diversion based on his view of legitimate medical practice. As explained below, the CSA's express limitations on the Attorney General's authority, and other indications from the statutory scheme, belie any notion that the Attorney General has been granted this implicit authority. Indeed, if "control" were given the expansive meaning required to sustain the Interpretive Rule, it would transform the carefully described [261] limits on the Attorney General's authority over registration and scheduling into mere suggestions.

    49

    We turn, next, to the registration provisions of the CSA. Before 1984, the Attorney General was required to register any physician who was authorized by his State. The Attorney General could only deregister a physician who falsified his application, was convicted of a felony relating to controlled substances, or had his state license or registration revoked. See 84 Stat. 1255. The CSA was amended in 1984 to allow the Attorney General to deny registration to an applicant "if he determines that the issuance of such registration would be inconsistent with the public interest." 21 U.S.C. § 823(f). Registration may also be revoked or suspended by the Attorney General on the same grounds. § 824(a)(4). In determining consistency with the public interest, the Attorney General must, as discussed above, consider five factors, including: the State's recommendation; compliance with state, federal, and local laws regarding controlled substances; and public health and safety. § 823(f).

    50

    The Interpretive Rule cannot be justified under this part of the statute. It does not undertake the five-factor analysis and concerns much more than registration. Nor does the Interpretive Rule on its face purport to be an application of the registration provision in § 823(f). It is, instead, an interpretation of the substantive federal law requirements (under 21 CFR § 1306.04 (2005)) for a valid prescription. It begins by announcing that assisting suicide is not a "legitimate medical purpose" under § 1306.04, and that dispensing controlled substances to assist a suicide violates the CSA. 66 Fed. Reg. 56608. Violation is a criminal offense, and often a felony, under 21 U.S.C. § 841 (2000 ed. and Supp. II). The Interpretive Rule thus purports to declare that using controlled substances for physician-assisted suicide is a crime, an authority that goes well beyond the Attorney General's statutory power to register or deregister.

    51

    [262] The Attorney General's deregistration power, of course, may carry implications for criminal enforcement because if a physician dispenses a controlled substance after he is deregistered, he violates § 841. The Interpretive Rule works in the opposite direction, however: It declares certain conduct criminal, placing in jeopardy the registration of any physician who engages in that conduct. To the extent the Interpretive Rule concerns registration, it simply states the obvious because one of the five factors the Attorney General must consider in deciding the "public interest" is "[c]ompliance with applicable State, Federal, or local laws relating to controlled substances." 21 U.S.C. § 823(f)(4). The problem with the design of the Interpretive Rule is that it cannot, and does not, explain why the Attorney General has the authority to decide what constitutes an underlying violation of the CSA in the first place. The explanation the Government seems to advance is that the Attorney General's authority to decide whether a physician's actions are inconsistent with the "public interest" provides the basis for the Interpretive Rule.

    52

    By this logic, however, the Attorney General claims extraordinary authority. If the Attorney General's argument were correct, his power to deregister necessarily would include the greater power to criminalize even the actions of registered physicians, whenever they engage in conduct he deems illegitimate. This power to criminalize—unlike his power over registration, which must be exercised only after considering five express statutory factors—would be unrestrained. It would be anomalous for Congress to have so painstakingly described the Attorney General's limited authority to deregister a single physician or schedule a single drug, but to have given him, just by implication, authority to declare an entire class of activity outside "the course of professional practice," and therefore a criminal violation of the CSA. See Federal Maritime Comm'n v. Seatrain Lines, Inc., 411 U.S. 726, 744 (1973) ("In light of these specific [263] grants of . . . authority, we are unwilling to construe the ambiguous provisions . . . to serve this purpose [of creating further authority]—a purpose for which it obviously was not intended").

    53

    Sutton v. United Air Lines, Inc., 527 U.S. 471 (1999), is instructive. The statute at issue was the Americans with Disabilities Act of 1990 (ADA), which, like the CSA, divides interpretive authority among various executive actors. The Court relied on "the terms and structure of the ADA" to decide that neither the Equal Employment Opportunity Commission (EEOC), nor any other agency, had authority to define "disability" in the ADA. Id., at 479. Specifically, the delegating provision stated that the EEOC "shall issue regulations . . . to carry out this subchapter," 42 U.S.C. § 12116, and the section of the statute defining "disability" was in a different subchapter. The Court did not accept the idea that because "the employment subchapter, i. e., `this subchapter,' includes other provisions that use the defined terms, . . . [t]he EEOC might elaborate, through regulations, on the meaning of `disability' . . . if elaboration is needed in order to `carry out' the substantive provisions of `this subchapter.'" 527 U.S., at 514 (Breyer, J., dissenting). See also Adams Fruit Co. v. Barrett, 494 U.S. 638, 649-650 (1990) (holding that a delegation of authority to promulgate motor vehicle safety "standards" did not include the authority to decide the pre-emptive scope of the federal statute because "[n]o such delegation regarding [the statute's] enforcement provisions is evident in the statute").

    54

    The same principle controls here. It is not enough that the terms "public interest," "public health and safety," and "Federal law" are used in the part of the statute over which the Attorney General has authority. The statutory terms "public interest" and "public health" do not call on the Attorney General, or any other executive official, to make an independent assessment of the meaning of federal law. The Attorney General did not base the Interpretive Rule on an [264] application of the five-factor test generally, or the "public health and safety" factor specifically. Even if he had, it is doubtful the Attorney General could cite the "public interest" or "public health" to deregister a physician simply because he deemed a controversial practice permitted by state law to have an illegitimate medical purpose.

    55

    As for the federal-law factor, though it does require the Attorney General to decide "[c]ompliance" with the law, it does not suggest that he may decide what the law says. Were it otherwise, the Attorney General could authoritatively interpret "State" and "local laws," which are also included in 21 U.S.C. § 823(f), despite the obvious constitutional problems in his doing so. Just as he must evaluate compliance with federal law in deciding about registration, the Attorney General must as surely evaluate compliance with federal law in deciding whether to prosecute; but this does not entitle him to Chevron deference. See Crandon v. United States, 494 U.S. 152, 177 (1990) (SCALIA, J., concurring in judgment) ("The Justice Department, of course, has a very specific responsibility to determine for itself what this statute means, in order to decide when to prosecute; but we have never thought that the interpretation of those charged with prosecuting criminal statutes is entitled to deference").

    56

    The limits on the Attorney General's authority to define medical standards for the care and treatment of patients bear also on the proper interpretation of § 871(b). This section allows the Attorney General to best determine how to execute "his functions." It is quite a different matter, however, to say that the Attorney General can define the substantive standards of medical practice as part of his authority. To find a delegation of this extent in § 871 would put that part of the statute in considerable tension with the narrowly defined delegation concerning control and registration. It would go, moreover, against the plain language of the text to treat a delegation for the "execution" of his functions as a further delegation to define other functions well beyond [265] the statute's specific grants of authority. When Congress chooses to delegate a power of this extent, it does so not by referring back to the administrator's functions but by giving authority over the provisions of the statute he is to interpret. See, e. g., National Cable & Telecommunications Assn., 545 U.S. 967; Household Credit Services, 541 U.S. 232.

    57

    The authority desired by the Government is inconsistent with the design of the statute in other fundamental respects. The Attorney General does not have the sole delegated authority under the CSA. He must instead share it with, and in some respects defer to, the Secretary, whose functions are likewise delineated and confined by the statute. The CSA allocates decisionmaking powers among statutory actors so that medical judgments, if they are to be decided at the federal level and for the limited objects of the statute, are placed in the hands of the Secretary. In the scheduling context, for example, the Secretary's recommendations on scientific and medical matters bind the Attorney General. The Attorney General cannot control a substance if the Secretary disagrees. 21 U.S.C. § 811(b). See H. R. Rep. No. 91-1444, pt. 1, p. 33 (1970) (the section "is not intended to authorize the Attorney General to undertake or support medical and scientific research [for the purpose of scheduling], which is within the competence of the Department of Health, Education, and Welfare").

    58

    In a similar vein the 1970 Act's regulation of medical practice with respect to drug rehabilitation gives the Attorney General a limited role; for it is the Secretary who, after consultation with the Attorney General and national medical groups, "determine[s] the appropriate methods of professional practice in the medical treatment of . . . narcotic addiction." 42 U.S.C. § 290bb-2a; see 21 U.S.C. § 823(g) (2000 ed. and Supp. II) (stating that the Attorney General shall register practitioners who dispense drugs for narcotics treatment when the Secretary has determined the applicant is qualified to treat addicts and the Attorney General has concluded [266] the applicant will comply with recordkeeping and security regulations); Moore, 423 U.S., at 144 (noting that in enacting the addiction-treatment provisions, Congress sought to change the fact "that `criminal prosecutions' in the past had turned on the opinions of federal prosecutors"); H. R. Rep. No. 93-884, p. 6 (1974) ("This section preserves the distinctions found in the [CSA] between the functions of the Attorney General and the Secretary . . . . All decisions of a medical nature are to be made by the Secretary . . . . Law enforcement decisions respecting the security of stocks of narcotic drugs and the maintenance of records on such drugs are to be made by the Attorney General").

    59

    Postenactment congressional commentary on the CSA's regulation of medical practice is also at odds with the Attorney General's claimed authority to determine appropriate medical standards. In 1978, in preparation for ratification of the Convention on Psychotropic Substances, Feb. 21, 1971, [1979-1980] 32 U.S. T. 543, T. I. A. S. No. 9725, Congress decided it would implement the United States' compliance through "the framework of the procedures and criteria for classification of substances provided in the" CSA. 21 U.S.C. § 801a(3). It did so to ensure that "nothing in the Convention will interfere with ethical medical practice in this country as determined by [the Secretary] on the basis of a consensus of the views of the American medical and scientific community." Ibid.

    60

    The structure of the CSA, then, conveys unwillingness to cede medical judgments to an executive official who lacks medical expertise. In interpreting statutes that divide authority, the Court has recognized: "Because historical familiarity and policymaking expertise account in the first instance for the presumption that Congress delegates interpretive lawmaking power to the agency rather than to the reviewing court, we presume here that Congress intended to invest interpretive power in the administrative actor in the best position to develop these attributes." Martin [267] v. Occupational Safety and Health Review Comm'n, 499 U.S. 144, 153 (1991) (citations omitted). This presumption works against a conclusion that the Attorney General has authority to make quintessentially medical judgments.

    61

    The Government contends the Attorney General's decision here is a legal, not a medical, one. This generality, however, does not suffice. The Attorney General's Interpretive Rule, and the Office of Legal Counsel memo it incorporates, place extensive reliance on medical judgments and the views of the medical community in concluding that assisted suicide is not a "legitimate medical purpose." See 66 Fed. Reg. 56608 (noting the "medical" distinctions between assisting suicide and giving sufficient medication to alleviate pain); Memorandum from Office of Legal Counsel to Attorney General (June 27, 2001), App. to Pet. for Cert. 121a-122a, and n. 17 (discussing the "Federal medical policy" against physician-assisted suicide), id., at 124a-130a (examining views of the medical community). This confirms that the authority claimed by the Attorney General is both beyond his expertise and incongruous with the statutory purposes and design.

    62

    The idea that Congress gave the Attorney General such broad and unusual authority through an implicit delegation in the CSA's registration provision is not sustainable. "Congress, we have held, does not alter the fundamental details of a regulatory scheme in vague terms or ancillary provisions—it does not, one might say, hide elephants in mouseholes." Whitman v. American Trucking Assns., Inc., 531 U.S. 457, 468 (2001); see FDA v. Brown & Williamson Tobacco Corp., 529 U.S. 120, 160 (2000) ("[W]e are confident that Congress could not have intended to delegate a decision of such economic and political significance to an agency in so cryptic a fashion").

    63

    The importance of the issue of physician-assisted suicide, which has been the subject of an "earnest and profound debate" across the country, Glucksberg, 521 U.S., at 735, makes the oblique form of the claimed delegation all the more suspect. [268] Under the Government's theory, moreover, the medical judgments the Attorney General could make are not limited to physician-assisted suicide. Were this argument accepted, he could decide whether any particular drug may be used for any particular purpose, or indeed whether a physician who administers any controversial treatment could be deregistered. This would occur, under the Government's view, despite the statute's express limitation of the Attorney General's authority to registration and control, with attendant restrictions on each of those functions, and despite the statutory purposes to combat drug abuse and prevent illicit drug trafficking.

    64

    We need not decide whether Chevron deference would be warranted for an interpretation issued by the Attorney General concerning matters closer to his role under the CSA, namely, preventing doctors from engaging in illicit drug trafficking. In light of the foregoing, however, the CSA does not give the Attorney General authority to issue the Interpretive Rule as a statement with the force of law.

    65

    If, in the course of exercising his authority, the Attorney General uses his analysis in the Interpretive Rule only for guidance in deciding when to prosecute or deregister, then the question remains whether his substantive interpretation is correct. Since the Interpretive Rule was not promulgated pursuant to the Attorney General's authority, its interpretation of "legitimate medical purpose" does not receive Chevron deference. Instead, it receives deference only in accordance with Skidmore. "The weight of such a judgment in a particular case will depend upon the thoroughness evident in its consideration, the validity of its reasoning, its consistency with earlier and later pronouncements, and all those factors which give it power to persuade, if lacking power to control." 323 U.S., at 140; see also Mead, 533 U.S., at 235 (noting that an opinion receiving Skidmore deference may "claim the merit of its writer's thoroughness, logic, and expertness, its fit with prior interpretations, and any other [269] sources of weight"). The deference here is tempered by the Attorney General's lack of expertise in this area and the apparent absence of any consultation with anyone outside the Department of Justice who might aid in a reasoned judgment. In any event, under Skidmore, we follow an agency's rule only to the extent it is persuasive, see Christensen v. Harris County, 529 U.S. 576, 587 (2000); and for the reasons given and for further reasons set out below, we do not find the Attorney General's opinion persuasive.

    66
    III
    67

    As we have noted before, the CSA "repealed most of the earlier antidrug laws in favor of a comprehensive regime to combat the international and interstate traffic in illicit drugs." Raich, 545 U.S., at 12. In doing so, Congress sought to "conquer drug abuse and to control the legitimate and illegitimate traffic in controlled substances." Ibid. It comes as little surprise, then, that we have not considered the extent to which the CSA regulates medical practice beyond prohibiting a doctor from acting as a drug "`pusher'" instead of a physician. Moore, 423 U.S., at 143. In Moore, we addressed a situation in which a doctor "sold drugs, not for legitimate purposes, but primarily for the profits to be derived therefrom." Id., at 135 (quoting H. R. Rep. No. 91-1444, pt. 1, at 10; internal quotation marks omitted). There the defendant, who had engaged in large-scale over-prescribing of methadone, "concede[d] in his brief that he did not observe generally accepted medical practices." 423 U.S., at 126. And in United States v. Oakland Cannabis Buyers' Cooperative, 532 U.S. 483 (2001), Congress' express determination that marijuana had no accepted medical use foreclosed any argument about statutory coverage of drugs available by a doctor's prescription.

    68

    In deciding whether the CSA can be read as prohibiting physician-assisted suicide, we look to the statute's text and design. The statute and our case law amply support the [270] conclusion that Congress regulates medical practice insofar as it bars doctors from using their prescription-writing powers as a means to engage in illicit drug dealing and trafficking as conventionally understood. Beyond this, however, the statute manifests no intent to regulate the practice of medicine generally. The silence is understandable given the structure and limitations of federalism, which allow the States "`great latitude under their police powers to legislate as to the protection of the lives, limbs, health, comfort, and quiet of all persons.'" Medtronic, Inc. v. Lohr, 518 U.S. 470, 475 (1996) (quoting Metropolitan Life Ins. Co. v. Massachusetts, 471 U.S. 724, 756 (1985)).

    69

    The structure and operation of the CSA presume and rely upon a functioning medical profession regulated under the States' police powers. The Attorney General can register a physician to dispense controlled substances "if the applicant is authorized to dispense . . . controlled substances under the laws of the State in which he practices." 21 U.S.C. § 823(f). When considering whether to revoke a physician's registration, the Attorney General looks not just to violations of federal drug laws; but he "shall" also consider "[t]he recommendation of the appropriate State licensing board or professional disciplinary authority" and the registrant's compliance with state and local drug laws. Ibid. The very definition of a "practitioner" eligible to prescribe includes physicians "licensed, registered, or otherwise permitted, by the United States or the jurisdiction in which he practices" to dispense controlled substances. § 802(21). Further cautioning against the conclusion that the CSA effectively displaces the States' general regulation of medical practice is the Act's pre-emption provision, which indicates that, absent a positive conflict, none of the Act's provisions should be "construed as indicating an intent on the part of the Congress to occupy the field in which that provision operates . . . to the exclusion of any State law on the same subject matter [271] which would otherwise be within the authority of the State." § 903.

    70

    Oregon's regime is an example of the state regulation of medical practice that the CSA presupposes. Rather than simply decriminalizing assisted suicide, ODWDA limits its exercise to the attending physicians of terminally ill patients, physicians who must be licensed by Oregon's Board of Medical Examiners. Ore. Rev. Stat. §§ 127.815, 127.800(10) (2003). The statute gives attending physicians a central role, requiring them to provide prognoses and prescriptions, give information about palliative alternatives and counseling, and ensure patients are competent and acting voluntarily. § 127.815. Any eligible patient must also get a second opinion from another registered physician, § 127.820, and the statute's safeguards require physicians to keep and submit to inspection detailed records of their actions, §§ 127.855, 127.865.

    71

    Even though regulation of health and safety is "primarily, and historically, a matter of local concern," Hillsborough County v. Automated Medical Laboratories, Inc., 471 U.S. 707, 719 (1985), there is no question that the Federal Government can set uniform national standards in these areas. See Raich, supra, at 9. In connection to the CSA, however, we find only one area in which Congress set general, uniform standards of medical practice. Title I of the Comprehensive Drug Abuse Prevention and Control Act of 1970, of which the CSA was Title II, provides:

    72

    "[The Secretary], after consultation with the Attorney General and with national organizations representative of persons with knowledge and experience in the treatment of narcotic addicts, shall determine the appropriate methods of professional practice in the medical treatment of the narcotic addiction of various classes of narcotic addicts, and shall report thereon from time to time to the Congress." § 4, 84 Stat. 1241, codified at 42 U.S.C. § 290bb-2a.

    73

    [272] This provision strengthens the understanding of the CSA as a statute combating recreational drug abuse, and also indicates that when Congress wants to regulate medical practice in the given scheme, it does so by explicit language in the statute.

    74

    In the face of the CSA's silence on the practice of medicine generally and its recognition of state regulation of the medical profession it is difficult to defend the Attorney General's declaration that the statute impliedly criminalizes physician-assisted suicide. This difficulty is compounded by the CSA's consistent delegation of medical judgments to the Secretary and its otherwise careful allocation of powers for enforcing the limited objects of the CSA. See Part II-B, supra. The Government's attempt to meet this challenge rests, for the most part, on the CSA's requirement that every Schedule II drug be dispensed pursuant to a "written prescription of a practitioner." 21 U.S.C. § 829(a). A prescription, the Government argues, necessarily implies that the substance is being made available to a patient for a legitimate medical purpose. The statute, in this view, requires an anterior judgment about the term "medical" or "medicine." The Government contends ordinary usage of these words ineluctably refers to a healing or curative art, which by these terms cannot embrace the intentional hastening of a patient's death. It also points to the teachings of Hippocrates, the positions of prominent medical organizations, the Federal Government, and the judgment of the 49 States that have not legalized physician-assisted suicide as further support for the proposition that the practice is not legitimate medicine. See Brief for Petitioners 22-24; Memorandum from Office of Legal Counsel to Attorney General, App. to Pet. for Cert. 124a-130a.

    75

    On its own, this understanding of medicine's boundaries is at least reasonable. The primary problem with the Government's argument, however, is its assumption that the CSA [273] impliedly authorizes an executive officer to bar a use simply because it may be inconsistent with one reasonable understanding of medical practice. Viewed alone, the prescription requirement may support such an understanding, but statutes "should not be read as a series of unrelated and isolated provisions." Gustafson v. Alloyd Co., 513 U.S. 561, 570 (1995). The CSA's substantive provisions and their arrangement undermine this assertion of an expansive federal authority to regulate medicine.

    76

    The statutory criteria for deciding what substances are controlled, determinations which are central to the Act, consistently connect the undefined term "drug abuse" with addiction or abnormal effects on the nervous system. When the Attorney General schedules drugs, he must consider a substance's psychic or physiological dependence liability. 21 U.S.C. § 811(c)(7). To classify a substance in Schedules II through V, the Attorney General must find abuse of the drug leads to psychological or physical dependence. § 812(b). Indeed, the differentiation of Schedules II through V turns in large part on a substance's habit-forming potential: The more addictive a substance, the stricter the controls. Ibid. When Congress wanted to extend the CSA's regulation to substances not obviously habit forming or psychotropic, moreover, it relied not on executive ingenuity, but rather on specific legislation. See § 1902(a) of the Anabolic Steroids Control Act of 1990, 104 Stat. 4851 (placing anabolic steroids in Schedule III).

    77

    The statutory scheme with which the CSA is intertwined further confirms a more limited understanding of the prescription requirement. When the Secretary considers Food and Drug Administration approval of a substance with "stimulant, depressant, or hallucinogenic effect," he must forward the information to the Attorney General for possible scheduling. Shedding light on Congress' understanding of drug abuse, this requirement appears under the heading "Abuse [274] potential." 21 U.S.C. § 811(f). Similarly, when Congress prepared to implement the Convention on Psychotropic Substances, it did so through the CSA. § 801a.

    78

    The Interpretive Rule rests on a reading of the prescription requirement that is persuasive only to the extent one scrutinizes the provision without the illumination of the rest of the statute. See Massachusetts v. Morash, 490 U.S. 107, 114-115 (1989). Viewed in its context, the prescription requirement is better understood as a provision that ensures patients use controlled substances under the supervision of a doctor so as to prevent addiction and recreational abuse. As a corollary, the provision also bars doctors from peddling to patients who crave the drugs for those prohibited uses. See Moore, 423 U.S., at 135, 143. To read prescriptions for assisted suicide as constituting "drug abuse" under the CSA is discordant with the phrase's consistent use throughout the statute, not to mention its ordinary meaning.

    79

    The Government's interpretation of the prescription requirement also fails under the objection that the Attorney General is an unlikely recipient of such broad authority, given the Secretary's primacy in shaping medical policy under the CSA, and the statute's otherwise careful allocation of decisionmaking powers. Just as the conventions of expression indicate that Congress is unlikely to alter a statute's obvious scope and division of authority through muffled hints, the background principles of our federal system also belie the notion that Congress would use such an obscure grant of authority to regulate areas traditionally supervised by the States' police power. It is unnecessary even to consider the application of clear statement requirements, see, e. g., United States v. Bass, 404 U.S. 336, 349 (1971); cf. BFP v. Resolution Trust Corporation, 511 U.S. 531, 544-546 (1994), or presumptions against pre-emption, see, e. g., Rush Prudential HMO, Inc. v. Moran, 536 U.S. 355, 387 (2002), to reach this commonsense conclusion. For all these reasons, we conclude the CSA's prescription requirement does not authorize [275] the Attorney General to bar dispensing controlled substances for assisted suicide in the face of a state medical regime permitting such conduct.

    80
    IV
    81

    The Government, in the end, maintains that the prescription requirement delegates to a single executive officer the power to effect a radical shift of authority from the States to the Federal Government to define general standards of medical practice in every locality. The text and structure of the CSA show that Congress did not have this far-reaching intent to alter the federal-state balance and the congressional role in maintaining it.

    82

    The judgment of the Court of Appeals is

    83

    Affirmed.

    84
    JUSTICE SCALIA, with whom CHIEF JUSTICE ROBERTS and JUSTICE THOMAS join, dissenting.
    85

    The Court concludes that the Attorney General lacked authority to declare assisted suicide illicit under the Controlled Substances Act (CSA), because the CSA is concerned only with "illicit drug dealing and trafficking," ante, at 270 (emphasis added). This question-begging conclusion is obscured by a flurry of arguments that distort the statute and disregard settled principles of our interpretive jurisprudence.

    86

    Contrary to the Court's analysis, this case involves not one but three independently sufficient grounds for reversing the Ninth Circuit's judgment. First, the Attorney General's interpretation of "legitimate medical purpose" in 21 CFR § 1306.04 (2005) (hereinafter Regulation) is clearly valid, given the substantial deference we must accord it under Auer v. Robbins, 519 U.S. 452, 461 (1997), and his two remaining conclusions follow naturally from this interpretation. See Part I, infra. Second, even if this interpretation of the Regulation is entitled to lesser deference or no deference [276] at all, it is by far the most natural interpretation of the Regulation—whose validity is not challenged here. This interpretation is thus correct even upon de novo review. See Part II, infra. Third, even if that interpretation of the Regulation were incorrect, the Attorney General's independent interpretation of the statutory phrase "public interest" in 21 U.S.C. §§ 824(a) and 823(f), and his implicit interpretation of the statutory phrase "public health and safety" in § 823(f)(5), are entitled to deference under Chevron U.S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984), and they are valid under Chevron. See Part III, infra. For these reasons, I respectfully dissent.

    87
    I
    88

    The Interpretive Rule issued by the Attorney General (hereinafter Directive) provides in relevant part as follows:

    89

    "For the reasons set forth in the OLC Opinion, I hereby determine that assisting suicide is not a `legitimate medical purpose' within the meaning of 21 CFR § 1306.04 (2001), and that prescribing, dispensing, or administering federally controlled substances to assist suicide violates the CSA. Such conduct by a physician registered to dispense controlled substances may `render his registration . . . inconsistent with the public interest' and therefore subject to possible suspension or revocation under 21 U.S.C. [§] 824(a)(4)." 66 Fed. Reg. 56608 (2001).

    90

    The Directive thus purports to do three distinct things: (1) to interpret the phrase "legitimate medical purpose" in the Regulation to exclude physician-assisted suicide; (2) to determine that prescribing, dispensing, and administering federally controlled substances to assist suicide violates the CSA; and (3) to determine that participating in physician-assisted suicide may render a practitioner's registration "inconsistent with the public interest" within the meaning of 21 U.S.C. §§ 823(f) and 824(a)(4) (which incorporates § 823(f) by reference). [277] The Court's analysis suffers from an unremitting failure to distinguish among these distinct propositions in the Directive.

    91

    As an initial matter, the validity of the Regulation's interpretation of "prescription" in § 829 to require a "legitimate medical purpose" is not at issue. Respondents conceded the validity of this interpretation in the lower court, see Oregon v. Ashcroft, 368 F.3d 1118, 1133 (CA9 2004), and they have not challenged it here. By its assertion that the Regulation merely restates the statutory standard of 21 U.S.C. § 830(b)(3)(A)(ii), see ante, at 257, the Court likewise accepts that the "legitimate medical purpose" interpretation for prescriptions is proper. See also ante, at 258 (referring to "legitimate medical purpose" as a "statutory phrase"). It is beyond dispute, then, that a "prescription" under § 829 must issue for a "legitimate medical purpose."

    92
    A
    93

    Because the Regulation was promulgated by the Attorney General, and because the Directive purported to interpret the language of the Regulation, see 66 Fed. Reg. 56608, this case calls for the straightforward application of our rule that an agency's interpretation of its own regulations is "controlling unless plainly erroneous or inconsistent with the regulation." Auer, supra, at 461 (internal quotation marks omitted). The Court reasons that Auer is inapplicable because the Regulation "does little more than restate the terms of the statute itself." Ante, at 257. "Simply put," the Court asserts, "the existence of a parroting regulation does not change the fact that the question here is not the meaning of the regulation but the meaning of the statute." Ibid.

    94

    To begin with, it is doubtful that any such exception to the Auer rule exists. The Court cites no authority for it, because there is none. To the contrary, our unanimous decision in Auer makes clear that broadly drawn regulations are entitled to no less respect than narrow ones. "A rule requiring [278] the Secretary to construe his own regulations narrowly would make little sense, since he is free to write the regulations as broadly as he wishes, subject only to the limits imposed by the statute." 519 U.S., at 463 (emphasis added).

    95

    Even if there were an antiparroting canon, however, it would have no application here. The Court's description of 21 CFR § 1306.04 (2005) as a regulation that merely "paraphrase[s] the statutory language," ante, at 257, is demonstrably false. In relevant part, the Regulation interprets the word "prescription" as it appears in 21 U.S.C. § 829, which governs the dispensation of controlled substances other than those on Schedule I (which may not be dispensed at all). Entitled "[p]rescriptions," § 829 requires, with certain exceptions not relevant here, "the written prescription of a practitioner" (usually a medical doctor) for the dispensation of Schedule II substances (§ 829(a)), "a written or oral prescription" for substances on Schedules III and IV (§ 829(b)), and no prescription but merely a "medical purpose" for the dispensation of Schedule V substances (§ 829(c)).

    96

    As used in this section, "prescription" is susceptible of at least three reasonable interpretations. First, it might mean any oral or written direction of a practitioner for the dispensation of drugs. See United States v. Moore, 423 U.S. 122, 137, n. 13 (1975) ("On its face § 829 addresses only the form that a prescription must take. . . . [Section] 829 by its terms does not limit the authority of a practitioner"). Second, in light of the requirement of a "medical purpose" for the dispensation of Schedule V substances, see § 829(c), it might mean a practitioner's oral or written direction for the dispensation of drugs that the practitioner believes to be for a legitimate medical purpose. See Webster's New International Dictionary 1954 (2d ed. 1950) (hereinafter Webster's Second) (defining "prescription" as "[a] written direction for the preparation and use of a medicine"); id., at 1527 (defining "medicine" as "[a]ny substance or preparation used in treating disease") (emphasis added). Finally, "prescription" might [279] refer to a practitioner's direction for the dispensation of drugs that serves an objectively legitimate medical purpose, regardless of the practitioner's subjective judgment about the legitimacy of the anticipated use. See ibid.

    97

    The Regulation at issue constricts or clarifies the statute by adopting the last and narrowest of these three possible interpretations of the undefined statutory term: "A prescription for a controlled substance to be effective must be issued for a legitimate medical purpose . . . ." 21 CFR § 1306.04(a) (2005). We have previously acknowledged that the Regulation gives added content to the text of the statute: "The medical purpose requirement explicit in subsection (c) [of § 829] could be implicit in subsections (a) and (b). Regulation § [1]306.04 makes it explicit." Moore, supra, at 137, n. 13.[2]

    98

    The Court points out that the Regulation adopts some of the phrasing employed in unrelated sections of the statute. See ante, at 257. This is irrelevant. A regulation that significantly clarifies the meaning of an otherwise ambiguous statutory provision is not a "parroting" regulation, regardless of the sources that the agency draws upon for the clarification. Moreover, most of the statutory phrases that the Court cites as appearing in the Regulation, see ibid. (citing 21 U.S.C. §§ 812(b) ("`currently accepted medical use'"), 829(c) ("`medical purpose'"), 802(21) ("`in the course of professional practice'")), are inapposite because they do not "parrot" the only phrase in the Regulation that the Directive purported to construe. See 66 Fed. Reg. 56608 ("I hereby [280] determine that assisting suicide is not a `legitimate medical purpose' within the meaning of 21 CFR § 1306.04 . . ."). None of them includes the key word "legitimate," which gives the most direct support to the Directive's theory that § 829(c) presupposes a uniform federal standard of medical practice.[3]

    99

    Since the Regulation does not run afowl (so to speak) of the Court's newly invented prohibition of "parroting"; and since the Directive represents the agency's own interpretation of that concededly valid regulation; the only question remaining is whether that interpretation is "plainly erroneous or inconsistent with the regulation"; otherwise, it is "controlling." Auer, 519 U.S., at 461 (internal quotation marks omitted). This is not a difficult question. The Directive is assuredly valid insofar as it interprets "prescription" to require a medical purpose that is "legitimate" as a matter of federal law—since that is an interpretation of "prescription" that we ourselves have adopted. Webb v. United States, 249 U.S. 96 (1919), was a prosecution under the Harrison Act of a doctor who wrote prescriptions of morphine "for the purpose of providing the user with morphine sufficient to keep him comfortable by maintaining his customary use," id., [281] at 99 (internal quotation marks omitted). The dispositive issue in the case was whether such authorizations were "prescriptions" within the meaning of § 2(b) of the Harrison Act, predecessor to the CSA. Ibid. We held that "to call such an order for the use of morphine a physician's prescription would be so plain a perversion of meaning that no discussion of the subject is required." Id., at 99-100. Like the Directive, this interprets "prescription" to require medical purpose that is legitimate as a matter of federal law. And the Directive is also assuredly valid insofar as it interprets "legitimate medical purpose" as a matter of federal law to exclude physician-assisted suicide, because that is not only a permissible but indeed the most natural interpretation of that phrase. See Part II, infra.

    100
    B
    101

    Even if the Regulation merely parroted the statute, and the Directive therefore had to be treated as though it construed the statute directly, see ante, at 257, the Directive would still be entitled to deference under Chevron. The Court does not take issue with the Solicitor General's contention that no alleged procedural defect, such as the absence of notice-and-comment rulemaking before promulgation of the Directive, renders Chevron inapplicable here. See Reply Brief for Petitioners 4 (citing Barnhart v. Walton, 535 U.S. 212, 219-222 (2002); 5 U.S.C. § 553(b)(3)(A) (exempting interpretive rules from notice-and-comment rulemaking)). Instead, the Court holds that the Attorney General lacks interpretive authority to issue the Directive at all, on the ground that the explicit delegation provision, 21 U.S.C. § 821 (2000 ed., Supp. V), limits his rulemaking authority to "registration and control," which (according to the Court) are not implicated by the Directive's interpretation of the prescription requirement. See ante, at 259-262.

    102

    Setting aside the implicit delegation inherent in Congress's use of the undefined term "prescription" in § 829, the Court's [282] reading of "control" in § 821 is manifestly erroneous. The Court urges, ante, at 260, that "control" is a term defined in part A of the subchapter (entitled "Introductory Provisions") to mean "to add a drug or other substance . . . to a schedule under part B of this subchapter," 21 U.S.C. § 802(5) (emphasis added). But § 821 is not included in "part B of this subchapter," which is entitled "Authority to Control; Standards and Schedules," and consists of the sections related to scheduling, 21 U.S.C. §§ 811-814 (2000 ed. and Supp. V), where the statutory definition is uniquely appropriate. Rather, § 821 is found in part C of the subchapter, §§ 821-830, entitled "Registration of Manufacturers, Distributors, and Dispensers of Controlled Substances," which includes all and only the provisions relating to the "manufacture, distribution, and dispensing of controlled substances," § 821. The artificial definition of "control" in § 802(5) has no conceivable application to the use of that word in § 821. Under that definition, "control" must take a substance as its direct object, see 21 U.S.C. § 802(5) ("to add a drug or other substance . . . to a schedule")—and that is how "control" is consistently used throughout part B. See, e. g., §§ 811(b) ("proceedings . . . to control a drug or other substance"), 811(c) ("each drug or other substance proposed to be controlled or removed from the schedules"), 811(d)(1) ("If control is required . . . the Attorney General shall issue an order controlling such drug . . ."), 812(b) ("Except where control is required . . . a drug or other substance may not be placed in any schedule . . ."). In § 821, by contrast, the term "control" has as its object, not "a drug or other substance," but rather the processes of "manufacture, distribution, and dispensing of controlled substances." It could not be clearer that the artificial definition of "control" in § 802(5) is inapplicable. It makes no sense to speak of "adding the manufacturing, distribution, and dispensing of substances to a schedule." We do not force term-of-art definitions into contexts where they plainly do not fit and produce nonsense. What [283] is obviously intended in § 821 is the ordinary meaning of "control"—namely, "[t]o exercise restraining or directing influence over; to dominate; regulate; hence, to hold from action; to curb," Webster's Second 580. "Control" is regularly used in this ordinary sense elsewhere in part C of the subchapter. See, e. g., 21 U.S.C. §§ 823(a)(1), (b)(1), (d)(1), (e)(1), (h)(1) ("maintenance of effective controls against diversion"); §§ 823(a)(5), (d)(5) ("establishment of effective control against diversion"); § 823(g)(2)(H)(i) ("to exercise supervision or control over the practice of medicine"); § 830(b)(1)(C) ("a listed chemical under the control of the regulated person"); § 830(c)(2)(D) ("chemical control laws") (emphasis added).

    103

    When the word is given its ordinary meaning, the Attorney General's interpretation of the prescription requirement of § 829 plainly "relat[es] to the . . . control of the . . . dispensing of controlled substances," 21 U.S.C. § 821 (2000 ed., Supp. V) (emphasis added), since a prescription is the chief requirement for "dispensing" such drugs, see § 829. The same meaning is compelled by the fact that § 821 is the first section not of part B of the subchapter, which deals entirely with "control" in the artificial sense, but of part C, every section of which relates to the "registration and control of the manufacture, distribution, and dispensing of controlled substances," § 821. See §§ 822 (persons required to register), 823 (registration requirements), 824 (denial, revocation, or suspension of registration), 825 (labeling and packaging), 826 (production quotas for controlled substances), 827 (recordkeeping and reporting requirements of registrants), 828 (order forms), 829 (prescription requirements), 830 (regulation of listed chemicals and certain machines). It would be peculiar for the first section of this part to authorize rulemaking for matters covered by the previous part. The only sensible interpretation of § 821 is that it gives the Attorney General interpretive authority over the provisions of part C, all of which "relat[e] to the registration and control of the [284] manufacture, distribution, and dispensing of controlled substances." These provisions include both the prescription requirement of § 829, and the criteria for registration and deregistration of §§ 823 and 824 (as relevant below, see Part III, infra).[4]

    104
    C
    105

    In sum, the Directive's construction of "legitimate medical purpose" is a perfectly valid agency interpretation of its own regulation; and if not that, a perfectly valid agency interpretation of the statute. No one contends that the construction is "plainly erroneous or inconsistent with the regulation," Bowles v. Seminole Rock & Sand Co., 325 U.S. 410, 414 (1945), or beyond the scope of ambiguity in the statute, see Chevron, 467 U.S., at 843. In fact, as explained below, the Directive provides the most natural interpretation of the Regulation and of the statute. The Directive thus definitively establishes that a doctor's order authorizing the dispensation of a Schedule II substance for the purpose of assisting a suicide is not a "prescription" within the meaning of § 829.

    106

    [285] Once this conclusion is established, the other two conclusions in the Directive follow inevitably. Under our reasoning in Moore, writing prescriptions that are illegitimate under § 829 is certainly not "in the [usual] course of professional practice" under § 802(21) and thus not "authorized by this subchapter" under § 841(a). See 423 U.S., at 138, 140-141. A doctor who does this may thus be prosecuted under § 841(a), and so it follows that such conduct "violates the Controlled Substances Act," 66 Fed. Reg. 56608. And since such conduct is thus not in "[c]ompliance with applicable . . . Federal . . . laws relating to controlled substances," 21 U.S.C. § 823(f)(4), and may also be fairly judged to "threaten the public health and safety," § 823(f)(5), it follows that "[s]uch conduct by a physician registered to dispense controlled substances may `render his registration . . . inconsistent with the public interest' and therefore subject to possible suspension or revocation under 21 U.S.C. [§] 824(a)(4)," 66 Fed. Reg. 56608 (emphasis added).

    107
    II
    108

    Even if the Directive were entitled to no deference whatever, the most reasonable interpretation of the Regulation and of the statute would produce the same result. Virtually every relevant source of authoritative meaning confirms that the phrase "legitimate medical purpose"[5] does not include intentionally assisting suicide. "Medicine" refers to "[t]he science and art dealing with the prevention, cure, or alleviation of disease." Webster's Second 1527. The use of the word "legitimate" connotes an objective standard of "medicine," and our presumption that the CSA creates a uniform federal law regulating the dispensation of controlled substances, see Mississippi Band of Choctaw Indians v. Holyfield, [286] 490 U.S. 30, 43 (1989), means that this objective standard must be a federal one. As recounted in detail in the memorandum for the Attorney General that is attached as an appendix to the Directive (OLC Memo), virtually every medical authority from Hippocrates to the current American Medical Association (AMA) confirms that assisting suicide has seldom or never been viewed as a form of "prevention, cure, or alleviation of disease," and (even more so) that assisting suicide is not a "legitimate" branch of that "science and art." See OLC Memo, App. to Pet. for Cert. 113a-130a. Indeed, the AMA has determined that "`[p]hysician-assisted suicide is fundamentally incompatible with the physician's role as healer.'" Washington v. Glucksberg, 521 U.S. 702, 731 (1997). "[T]he overwhelming weight of authority in judicial decisions, the past and present policies of nearly all of the States and of the Federal Government, and the clear, firm and unequivocal views of the leading associations within the American medical and nursing professions, establish that assisting in suicide . . . is not a legitimate medical purpose." OLC Memo, supra, at 129a. See also Glucksberg, supra, at 710, n. 8 (prohibitions or condemnations of assisted suicide in 50 jurisdictions, including 47 States, the District of Columbia, and 2 Territories).

    109

    In the face of this "overwhelming weight of authority," the Court's admission that "[o]n its own, this understanding of medicine's boundaries is at least reasonable," ante, at 272 (emphasis added), tests the limits of understatement. The only explanation for such a distortion is that the Court confuses the normative inquiry of what the boundaries of medicine should be—which it is laudably hesitant to undertake— with the objective inquiry of what the accepted definition of "medicine" is. The same confusion is reflected in the Court's remarkable statement that "[t]he primary problem with the Government's argument . . . is its assumption that the CSA impliedly authorizes an executive officer to bar a use simply [287] because it may be inconsistent with one reasonable understanding of medical practice." Ante, at 272-273 (emphasis added). The fact that many in Oregon believe that the boundaries of "legitimate medicine" should be extended to include assisted suicide does not change the fact that the overwhelming weight of authority (including the 47 States that condemn physician-assisted suicide) confirms that they have not yet been so extended. Not even those of our Eighth Amendment cases most generous in discerning an "evolution" of national standards would have found, on this record, that the concept of "legitimate medicine" has evolved so far. See Roper v. Simmons, 543 U.S. 551, 564-567 (2005).

    110

    The Court contends that the phrase "legitimate medical purpose" cannot be read to establish a broad, uniform federal standard for the medically proper use of controlled substances. Ante, at 268. But it also rejects the most plausible alternative proposition, urged by the State, that any use authorized under state law constitutes a "legitimate medical purpose." (The Court is perhaps leery of embracing this position because the State candidly admitted at oral argument that, on its view, a State could exempt from the CSA's coverage the use of morphine to achieve euphoria.) Instead, the Court reverse-engineers an approach somewhere between a uniform national standard and a state-by-state approach, holding (with no basis in the CSA's text) that "legitimate medical purpose" refers to all uses of drugs unrelated to "addiction and recreational abuse." Ante, at 274. Thus, though the Court pays lipservice to state autonomy, see ante, at 269-271, its standard for "legitimate medical purpose" is in fact a hazily defined federal standard based on its purposive reading of the CSA, and extracted from obliquely relevant sections of the Act. In particular, relying on its observation that the criteria for scheduling controlled substances are primarily concerned with "addiction or abnormal effects on the nervous system," ante, at 273 (citing 21 [288] U.S.C. §§ 811(c)(7), 812(b), 811(f), 801a), the Court concludes that the CSA's prescription requirement must be interpreted in light of this narrow view of the statute's purpose.

    111

    Even assuming, however, that the principal concern of the CSA is the curtailment of "addiction and recreational abuse," there is no reason to think that this is its exclusive concern. We have repeatedly observed that Congress often passes statutes that sweep more broadly than the main problem they were designed to address. "[S]tatutory prohibitions often go beyond the principal evil to cover reasonably comparable evils, and it is ultimately the provisions of our laws rather than the principal concerns of our legislators by which we are governed." Oncale v. Sundowner Offshore Services, Inc., 523 U.S. 75, 79 (1998). See also H. J. Inc. v. Northwestern Bell Telephone Co., 492 U.S. 229, 248 (1989).

    112

    The scheduling provisions of the CSA on which the Court relies confirm that the CSA's "design," ante, at 269, is not as narrow as the Court asserts. In making scheduling determinations, the Attorney General must not only consider a drug's "psychic or physiological dependence liability" as the Court points out, ante, at 273 (citing 21 U.S.C. § 811(c)(7)), but must also consider such broad factors as "[t]he state of current scientific knowledge regarding the drug or other substance," § 811(c)(3), and (most notably) "[w]hat, if any, risk there is to the public health," § 811(c)(6). If the latter factor were limited to addiction-related health risks, as the Court supposes, it would be redundant of § 811(c)(7). Moreover, in making registration determinations regarding manufacturers and distributors, the Attorney General "shall" consider "such other factors as may be relevant to and consistent with the public health and safety," §§ 823(a)(6), (b)(5), (d)(6), (e)(5) (emphasis added)—over and above the risk of "diversion" of controlled substances, §§ 823(a)(1), (a)(5), (b)(1), (d)(1), (d)(5), (e)(1). And, most relevant of all, in registering and deregistering physicians, the Attorney General "may deny an application [289] for such registration if he determines that the issuance of such registration would be inconsistent with the public interest," § 823(f); see also § 824(a)(4), and in making that determination "shall" consider "[s]uch other conduct which may threaten the public health and safety," § 823(f)(5). All of these provisions, not just those selectively cited by the Court, shed light upon the CSA's repeated references to the undefined term "abuse." See §§ 811(a)(1)(A), (c)(1), (c)(4), (c)(5); §§ 812(b)(1)(A), (b)(2)(A), (b)(3)(A), (b)(4)(A), (b)(5)(A).

    113

    By disregarding all these public-interest, public-health, and public-safety objectives, and limiting the CSA to "addiction and recreational abuse," the Court rules out the prohibition of anabolic-steroid use for bodybuilding purposes. It seeks to avoid this consequence by invoking the Anabolic Steroids Control Act of 1990, 104 Stat. 4851. Ante, at 273. But the only effect of that legislation is to make anabolic steroids controlled drugs under Schedule III of the CSA. If the only basis for control is (as the Court says) "addiction and recreational abuse," dispensation of these drugs for bodybuilding could not be proscribed.

    114

    Although, as I have described, the Court's opinion no more defers to state law than does the Directive, the Court relies on two provisions for the conclusion that "[t]he structure and operation of the CSA presume and rely upon a functioning medical profession regulated under the States' police powers," ante, at 270—namely, the registration provisions of § 823(f) and the nonpre-emption provision of § 903. Reliance on the former is particularly unfortunate, because the Court's own analysis recounts how Congress amended § 823(f) in 1984 in order to liberate the Attorney General's power over registration from the control of state regulators. See ante, at 261; 21 U.S.C. § 823(f); see also Brief for Petitioners 34-35. And the nonpre-emption clause is embarrassingly inapplicable, since it merely disclaims field pre-emption, and affirmatively prescribes federal pre-emption [290] whenever state law creates a conflict.[6] In any event, the Directive does not purport to pre-empt state law in any way, not even by conflict pre-emption—unless the Court is under the misimpression that some States require assisted suicide. The Directive merely interprets the CSA to prohibit, like countless other federal criminal provisions, conduct that happens not to be forbidden under state law (or at least the law of the State of Oregon).

    115

    With regard to the CSA's registration provisions, 21 U.S.C. §§ 823(f), 824(a), the Court argues that the statute cannot fairly be read to "`hide elephants in mouseholes'" by delegating to the Attorney General the power to determine the legitimacy of medical practices in "`vague terms or ancillary provisions.'" Ante, at 267 (quoting Whitman v. American Trucking Assns., Inc., 531 U.S. 457, 468 (2001)). This case bears not the remotest resemblance to Whitman, which held that "Congress . . . does not alter the fundamental details of a regulatory scheme in vague terms or ancillary provisions." Ibid. (emphasis added). The Attorney General's power to issue regulations against questionable uses of controlled substances in no way alters "the fundamental details" of the CSA. I am aware of only four areas in which the Department of Justice has exercised that power to regulate uses of controlled substances unrelated to "addiction and recreational abuse" as the Court apparently understands that phrase: assisted suicide, aggressive pain management therapy, anabolic-steroid use, and cosmetic weight-loss therapy. See, e. g., In re Harline, 65 Fed. Reg. 5665, 5667 (2000) (weight loss); In re Tecca, 62 Fed. Reg. 12842, 12846 (1997) (anabolic steroids); In re Roth, 60 Fed. Reg. 62262, 62263, 62267 (1995) (pain management). There is no indication that [291] enforcement in these areas interferes with the prosecution of "drug abuse" as the Court understands it. Unlike in Whitman, the Attorney General's additional power to address other forms of drug "abuse" does absolutely nothing to undermine the central features of this regulatory scheme. Of course it was critical to our analysis in Whitman that the language of the provision did not bear the meaning that respondents sought to give it. See 531 U.S., at 465. Here, for the reasons stated above, the provision is most naturally interpreted to incorporate a uniform federal standard for legitimacy of medical practice.[7]

    116

    Finally, respondents argue that the Attorney General must defer to state-law judgments about what constitutes legitimate medicine, on the ground that Congress must speak clearly to impose such a uniform federal standard upon the States. But no line of our clear-statement cases is applicable here. The canon of avoidance does not apply, since the Directive does not push the outer limits of Congress's commerce power, compare Solid Waste Agency of Northern Cook Cty. v. Army Corps of Engineers, 531 U.S. 159, 172 (2001) (regulation of isolated ponds), with United States v. Sullivan, 332 U.S. 689, 698 (1948) (regulation of labeling of drugs shipped in interstate commerce), or impinge on a core aspect of state sovereignty, cf. Atascadero State Hospital v. Scanlon, 473 U.S. 234, 242 (1985) (sovereign immunity); Gregory v. Ashcroft, 501 U.S. 452, 460 (1991) (qualifications of state government officials). The clear-statement rule based on the presumption against pre-emption does not [292] apply because the Directive does not pre-empt any state law, cf. id., at 456-457; Rush Prudential HMO, Inc. v. Moran, 536 U.S. 355, 359 (2002). And finally, no clear statement is required on the ground that the Directive intrudes upon an area traditionally reserved exclusively to the States, cf. BFP v. Resolution Trust Corporation, 511 U.S. 531, 544 (1994) (state regulation of titles to real property), because the Federal Government has pervasively regulated the dispensation of drugs for over 100 years. See generally Brief for Pro-Life Legal Defense Fund et al. as Amici Curiae 3-15. It would be a novel and massive expansion of the clear-statement rule to apply it in a commerce case not involving pre-emption or constitutional avoidance, merely because Congress has chosen to prohibit conduct that a State has made a contrary policy judgment to permit. See Sullivan, supra, at 693.

    117
    III
    118

    Even if the Regulation did not exist and "prescription" in § 829 could not be interpreted to require a "legitimate medical purpose," the Directive's conclusion that "prescribing, dispensing, or administering federally controlled substances. . . by a physician . . . may `render his registration . . . inconsistent with the public interest' and therefore subject to possible suspension or revocation under 21 U.S.C. [§] 824(a)(4)," 66 Fed. Reg. 56608, would nevertheless be unassailable in this Court.

    119

    Sections 823(f) and 824(a) explicitly grant the Attorney General the authority to register and deregister physicians, and his discretion in exercising that authority is spelled out in very broad terms. He may refuse to register or deregister if he determines that registration is "inconsistent with the public interest," 21 U.S.C. § 823(f), after considering five factors, the fifth of which is "[s]uch other conduct which may threaten the public health and safety," § 823(f)(5). See also In re Arora, 60 Fed. Reg. 4447, 4448 (1995) ("It is well established that these factors are to be considered in the disjunctive, [293] i. e., the Deputy Administrator may properly rely on any one or a combination of factors, and give each factor the weight he deems appropriate"). As the Court points out, these broad standards were enacted in the 1984 amendments for the specific purpose of freeing the Attorney General's discretion over registration from the decisions of state authorities. See ante, at 261.

    120

    The fact that assisted-suicide prescriptions are issued in violation of § 829 is of course sufficient to support the Directive's conclusion that issuing them may be cause for deregistration: such prescriptions would violate the fourth factor of § 823(f), namely, "[c]ompliance with applicable . . . Federal . . . laws relating to controlled substances," 21 U.S.C. § 823(f)(4). But the Attorney General did not rely solely on subsection (f)(4) in reaching his conclusion that registration would be "inconsistent with the public interest"; nothing in the text of the Directive indicates that. Subsection (f)(5) ("[s]uch other conduct which may threaten the public health and safety") provides an independent, alternative basis for the Directive's conclusion regarding deregistration—provided that the Attorney General has authority to interpret "public interest" and "public health and safety" in § 823(f) to exclude assisted suicide.

    121

    Three considerations make it perfectly clear that the statute confers authority to interpret these phrases upon the Attorney General. First, the Attorney General is solely and explicitly charged with administering the registration and deregistration provisions. See §§ 823(f), 824(a). By making the criteria for such registration and deregistration such obviously ambiguous factors as "public interest" and "public health and safety," Congress implicitly (but clearly) gave the Attorney General authority to interpret those criteria— whether or not there is any explicit delegation provision in the statute. "Sometimes the legislative delegation to an agency on a particular question is implicit rather than explicit. In such a case, a court may not substitute its own [294] construction of a statutory provision for a reasonable interpretation made by the administrator of an agency." Chevron, 467 U.S., at 844. The Court's exclusive focus on the explicit delegation provisions is, at best, a fossil of our pre-Chevron era; at least since Chevron, we have not conditioned our deferral to agency interpretations upon the existence of explicit delegation provisions. United States v. Mead Corp., 533 U.S. 218, 229 (2001), left this principle of implicit delegation intact.

    122

    Second, even if explicit delegation were required, Congress provided it in § 821, which authorizes the Attorney General to "promulgate rules and regulations . . . relating to the registration and control of the manufacture, distribution, and dispensing of controlled substances . . . ." (Emphasis added.) Because "dispensing" refers to the delivery of a controlled substance "pursuant to the lawful order of, a practitioner," 21 U.S.C. § 802(10), the deregistration of such practitioners for writing impermissible orders "relat[es] to the registration . . . of the . . . dispensing" of controlled substances, 21 U.S.C. § 821 (2000 ed., Supp. V).

    123

    Third, § 821 also gives the Attorney General authority to promulgate rules and regulations "relating to the . . . control of the . . . dispensing of controlled substances." As discussed earlier, it is plain that the ordinary meaning of "control" must apply to § 821, so that the plain import of the provision is to grant the Attorney General rulemaking authority over all the provisions of part C of the CSA, §§ 821-830 (main ed. and Supp. 2005). Registering and deregistering the practitioners who issue the prescriptions necessary for lawful dispensation of controlled substances plainly "relat[es] to the . . . control of the . . . dispensing of controlled substances." § 821 (Supp. 2005).

    124

    The Attorney General is thus authorized to promulgate regulations interpreting §§ 823(f) and 824(a), both by implicit delegation in § 823(f) and by two grounds of explicit delegation in § 821. The Court nevertheless holds that this triply [295] unambiguous delegation cannot be given full effect because "the design of the statute," ante, at 265, evinces the intent to grant the Secretary of Health and Human Services exclusive authority over scientific and medical determinations. This proposition is not remotely plausible. The Court cites as authority for the Secretary's exclusive authority two specific areas in which his medical determinations are said to be binding on the Attorney General—with regard to the "scientific and medical evaluation" of a drug's effects that precedes its scheduling, § 811(b), and with regard to "the appropriate methods of professional practice in the medical treatment of the narcotic addiction of various classes of narcotic addicts," 42 U.S.C. § 290bb-2a; see also 21 U.S.C. § 823(g) (2000 ed. and Supp. II). See ante, at 265-266. Far from establishing a general principle of Secretary supremacy with regard to all scientific and medical determinations, the fact that Congress granted the Secretary specifically defined authority in the areas of scheduling and addiction treatment, without otherwise mentioning him in the registration provisions, suggests, to the contrary, that Congress envisioned no role for the Secretary in that area—where, as we have said, interpretive authority was both implicitly and explicitly conferred upon the Attorney General.

    125

    Even if we could rewrite statutes to accord with sensible "design," it is far from a certainty that the Secretary, rather than the Attorney General, ought to control the registration of physicians. Though registration decisions sometimes require judgments about the legitimacy of medical practices, the Department of Justice has seemingly had no difficulty making them. See In re Harline, 65 Fed. Reg. 5665; In re Tecca, 62 Fed. Reg. 12842; In re Roth, 60 Fed. Reg. 62262. But unlike decisions about whether a substance should be scheduled or whether a narcotics addiction treatment is legitimate, registration decisions are not exclusively, or even primarily, concerned with "medical [and] scientific" factors. See 21 U.S.C. § 823(f). Rather, the decision to register, or [296] to bring an action to deregister, an individual physician implicates all the policy goals and competing enforcement priorities that attend any exercise of prosecutorial discretion. It is entirely reasonable to think (as Congress evidently did) that it would be easier for the Attorney General occasionally to make judgments about the legitimacy of medical practices than it would be for the Secretary to get into the business of law enforcement. It is, in other words, perfectly consistent with an intelligent "design of the statute" to give the Nation's chief law enforcement official, not its chief health official, broad discretion over the substantive standards that govern registration and deregistration. That is especially true where the contested "scientific and medical" judgment at issue has to do with the legitimacy of physician-assisted suicide, which ultimately rests, not on "science" or "medicine," but on a naked value judgment. It no more depends upon a "quintessentially medical judgmen[t]," ante, at 267, than does the legitimacy of polygamy or eugenic infanticide. And it requires no particular medical training to undertake the objective inquiry into how the continuing traditions of Western medicine have consistently treated this subject. See OLC Memo, App. to Pet. for Cert. 113a-130a. The Secretary's supposedly superior "medical expertise" to make "medical judgments," ante, at 266, is strikingly irrelevant to the case at hand.

    126

    The Court also reasons that, even if the CSA grants the Attorney General authority to interpret § 823(f), the Directive does not purport to exercise that authority, because it "does not undertake the five-factor analysis" of § 823(f) and does not "on its face purport to be an application of the registration provision in § 823(f)." Ante, at 261 (emphasis added). This reasoning is sophistic. It would be improper—indeed, impossible—for the Attorney General to "undertake the five-factor analysis" of § 823(f) and to "appl[y] the registration provision" outside the context of an actual enforcement proceeding. But of course the Attorney General [297] may issue regulations to clarify his interpretation of the five factors, and to signal how he will apply them in future enforcement proceedings. That is what the Directive plainly purports to do by citing § 824(a)(4), and that is why the Directive's conclusion on deregistration is couched in conditional terms: "Such conduct by a physician . . . may `render his registration . . . inconsistent with the public interest' and therefore subject to possible suspension or revocation under 21 U.S.C. [§] 824(a)(4)." 66 Fed. Reg. 56608 (emphasis added).

    127

    It follows from what we have said that the Attorney General's authoritative interpretations of "public interest" and "public health and safety" in § 823(f) are subject to Chevron deference. As noted earlier, the Court does not contest that the absence of notice-and-comment procedures for the Directive renders Chevron inapplicable. And there is no serious argument that "Congress has directly spoken to the precise question at issue," or that the Directive's interpretations of "public health and safety" and "inconsistent with the public interest" are not "permissible." Chevron, 467 U.S., at 842-843. On the latter point, in fact, the condemnation of assisted suicide by 50 American jurisdictions supports the Attorney General's view. The Attorney General may therefore weigh a physician's participation in assisted suicide as a factor counseling against his registration, or in favor of deregistration, under § 823(f).

    128

    In concluding to the contrary, the Court merely presents the conclusory assertion that "it is doubtful the Attorney General could cite the `public interest' or `public health' to deregister a physician simply because he deemed a controversial practice permitted by state law to have an illegitimate medical purpose." Ante, at 264. But why on earth not?—especially when he has interpreted the relevant statutory factors in advance to give fair warning that such a practice is "inconsistent with the public interest." The Attorney General's discretion to determine the public interest in this [298] area is admittedly broad—but certainly no broader than other congressionally conferred executive powers that we have upheld in the past. See, e. g., National Broadcasting Co. v. United States, 319 U.S. 190, 216-217 (1943) ("public interest"); New York Central Securities Corp. v. United States, 287 U.S. 12, 24-25 (1932) (same); see also Mistretta v. United States, 488 U.S. 361, 415-416 (1989) (SCALIA, J., dissenting).

    129

    * * *

    130

    In sum, the Directive's first conclusion—namely, that physician-assisted suicide is not a "legitimate medical purpose"—is supported both by the deference we owe to the agency's interpretation of its own regulations and by the deference we owe to its interpretation of the statute. The other two conclusions—(2) that prescribing controlled drugs to assist suicide violates the CSA, and (3) that such conduct is also "inconsistent with the public interest"—are inevitable consequences of that first conclusion. Moreover, the third conclusion, standing alone, is one that the Attorney General is authorized to make.

    131

    The Court's decision today is perhaps driven by a feeling that the subject of assisted suicide is none of the Federal Government's business. It is easy to sympathize with that position. The prohibition or deterrence of assisted suicide is certainly not among the enumerated powers conferred on the United States by the Constitution, and it is within the realm of public morality (bonos mores) traditionally addressed by the so-called police power of the States. But then, neither is prohibiting the recreational use of drugs or discouraging drug addiction among the enumerated powers. From an early time in our national history, the Federal Government has used its enumerated powers, such as its power to regulate interstate commerce, for the purpose of protecting public morality—for example, by banning the interstate shipment of lottery tickets, or the interstate transport of women for immoral purposes. See Hoke v. United States, [299] 227 U.S. 308, 321-323 (1913); Lottery Case, 188 U.S. 321, 356 (1903). Unless we are to repudiate a long and well-established principle of our jurisprudence, using the federal commerce power to prevent assisted suicide is unquestionably permissible. The question before us is not whether Congress can do this, or even whether Congress should do this; but simply whether Congress has done this in the CSA. I think there is no doubt that it has. If the term "legitimate medical purpose" has any meaning, it surely excludes the prescription of drugs to produce death.

    132

    For the above reasons, I respectfully dissent from the judgment of the Court.

    133
    JUSTICE THOMAS, dissenting.
    134

    When Angel Raich and Diane Monson challenged the application of the Controlled Substances Act (CSA), 21 U.S.C. § 801 et seq., to their purely intrastate possession of marijuana for medical use as authorized under California law, a majority of this Court (a mere seven months ago) determined that the CSA effectively invalidated California's law because "the CSA is a comprehensive regulatory regime specifically designed to regulate which controlled substances can be utilized for medicinal purposes, and in what manner." Gonzales v. Raich, 545 U.S. 1, 27 (2005) (emphasis added). The majority employed unambiguous language, concluding that the "manner" in which controlled substances can be utilized "for medicinal purposes" is one of the "core activities regulated by the CSA." Id., at 28. And, it described the CSA as "creating a comprehensive framework for regulating the production, distribution, and possession of . . . `controlled substances,'" including those substances that "`have a useful and legitimate medical purpose,'" in order to "foster the beneficial use of those medications" and "to prevent their misuse." Id., at 24.

    135

    Today the majority beats a hasty retreat from these conclusions. Confronted with a regulation that broadly requires [300] all prescriptions to be issued for a "legitimate medical purpose," 21 CFR § 1306.04(a) (2005), a regulation recognized in Raich as part of the Federal Government's "closed . . . system" for regulating the "manner" in "which controlled substances can be utilized for medicinal purposes," 545 U.S., at 13, 27, the majority rejects the Attorney General's admittedly "at least reasonable," ante, at 272, determination that administering controlled substances to facilitate a patient's death is not a "`legitimate medical purpose.'" The majority does so based on its conclusion that the CSA is only concerned with the regulation of "medical practice insofar as it bars doctors from using their prescription-writing powers as a means to engage in illicit drug dealing and trafficking as conventionally understood." Ante, at 270. In other words, in stark contrast to Raich's broad conclusions about the scope of the CSA as it pertains to the medicinal use of controlled substances, today this Court concludes that the CSA is merely concerned with fighting "`drug abuse'" and only insofar as that abuse leads to "addiction or abnormal effects on the nervous system."[8] Ante, at 273.

    136

    The majority's newfound understanding of the CSA as a statute of limited reach is all the more puzzling because it rests upon constitutional principles that the majority of the Court rejected in Raich. Notwithstanding the States' "`traditional police powers to define the criminal law and to protect the health, safety, and welfare of their citizens,'" 545 U.S., at 30, n. 38, the Raich majority concluded that the CSA applied to the intrastate possession of marijuana for medicinal purposes authorized by California law because "Congress could have rationally" concluded that such an application was necessary to the regulation of the "larger interstate marijuana market." Id., at 30, 32. Here, by contrast, the majority's [301] restrictive interpretation of the CSA is based in no small part on "the structure and limitations of federalism, which allow the States `"great latitude under their police powers to legislate as to the protection of the lives, limbs, health, comfort, and quiet of all persons."'" Ante, at 270 (quoting Medtronic, Inc. v. Lohr, 518 U.S. 470, 475 (1996), in turn quoting Metropolitan Life Ins. Co. v. Massachusetts, 471 U.S. 724, 756 (1985)). According to the majority, these "background principles of our federal system . . . belie the notion that Congress would use . . . an obscure grant of authority to regulate areas traditionally supervised by the States' police power." Ante, at 274.

    137

    Of course there is nothing "obscure" about the CSA's grant of authority to the Attorney General. Ante, p. 275 (SCALIA, J., dissenting). And, the Attorney General's conclusion that the CSA prohibits the States from authorizing physician assisted suicide is admittedly "at least reasonable," ante, at 272 (opinion of the Court), and is therefore entitled to deference. Ante, at 284-285 (Scalia, J., dissenting). While the scope of the CSA and the Attorney General's power thereunder are sweeping, and perhaps troubling, such expansive federal legislation and broad grants of authority to administrative agencies are merely the inevitable and inexorable consequence of this Court's Commerce Clause and separation-ofpowers jurisprudence. See, e. g., Raich, supra; Whitman v. American Trucking Assns., Inc., 531 U.S. 457 (2001).

    138

    I agree with limiting the applications of the CSA in a manner consistent with the principles of federalism and our constitutional structure. Raich, supra, at 74 (THOMAS, J., dissenting); cf. Whitman, supra, at 486-487 (THOMAS, J., concurring) (noting constitutional concerns with broad delegations of authority to administrative agencies). But that is now water over the dam. The relevance of such considerations was at its zenith in Raich, when we considered whether the CSA could be applied to the intrastate possession of a controlled substance consistent with the limited federal powers [302] enumerated by the Constitution. Such considerations have little, if any, relevance where, as here, we are merely presented with a question of statutory interpretation, and not the extent of constitutionally permissible federal power. This is particularly true where, as here, we are interpreting broad, straightforward language within a statutory framework that a majority of this Court has concluded is so comprehensive that it necessarily nullifies the States' "`traditional . . . powers . . . to protect the health, safety, and welfare of their citizens.'"[9] Raich, supra, at 30, n. 38. The Court's reliance upon the constitutional principles that it rejected in Raich—albeit under the guise of statutory interpretation —is perplexing to say the least. Accordingly, I respectfully dissent.

    139

    [1] Briefs of amici curiae urging reversal were filed for the American Center for Law and Justice by Jay Alan Sekulow, Colby M. May, James M. Henderson, Sr., Walter M. Weber, Thomas P. Monaghan, and Charles E. Rice; for Americans United for Life by Nikolas T. Nikas; for the Catholic Medical Association by Teresa Stanton Collett; for the Christian Medical Association et al. by Steven H. Aden, Gregory S. Baylor, and Kimberlee W. Colby; for Focus on the Family et al. by William Wagner, Nelson P. Miller, Stephen W. Reed, and Patrick A. Trueman; for the International Task Force on Euthanasia and Assisted Suicide by Rita L. Marker; for Liberty Counsel by Mathew D. Staver, Erik W. Stanley, Rena M. Lindevaldsen, and Mary E. McAlister; for the National Association of Pro-Life Nurses by Daniel Avila; for the National Legal Center for the Medically Dependent & Disabled, Inc., by James Bopp, Jr., Thomas J. Marzen, and Richard E. Coleson; for Not Dead Yet et al. by Max Lapertosa; for the Pro-Life Legal Defense Fund et al. by Dwight G. Duncan, Thomas M. Harvey, and Richard F. Collier, Jr.; for the Thomas More Society by Paul Benjamin Linton and Thomas Brejcha; for the United States Conference of Catholic Bishops et al. by Mark E. Chopko and Michael F. Moses; and for Senator Rick Santorum et al. by Donald A. Daugherty, Jr.

    140

    Briefs of amici curiae urging affirmance were filed for the State of California et al. by Bill Lockyer, Attorney General of California, and Taylor S. Carey, Special Assistant Attorney General, and by the Attorneys General for their respective jurisdictions as follows: Robert J. Spagnoletti of the District of Columbia, Jim Hood of Mississippi, Jeremiah W. (Jay) Nixon of Missouri, and Mike McGrath of Montana; for the American Civil Liberties Union et al. by Andrew L. Frey, David M. Gossett, Steven R. Shapiro, and Charles F. Hinkle; for the American College of Legal Medicine by Miles J. Zaremski; for the American Public Health Association by David T. Goldberg, Sean H. Donahue, and Daniel N. Abrahamson; for Autonomy, Inc., et al. by Amy R. Sabrin; for the Cato Institute by Pamela Harris; for the Coalition of Medical Associations and Societies et al. by Geoffrey J. Michael; for the Coalition of Mental Health Professionals by Steven Alan Reiss; for Healthlaw Professors by Arthur B. LaFrance; for Members of the Oregon Congressional Delegation by William R. Stein; for Margaret P. Battin et al. by Rebecca P. Dick and Ronald A. Lindsay; for Richard Briffault et al. by David W. Ogden and Paul R. Q. Wolfson; and for 52 Religious and Religious Freedom Organizations and Leaders by Gregory A. Castanias and Lawrence D. Rosenberg.

    141

    Briefs of amici curiae were filed for Physicians for Compassionate Care Educational Foundation by Gregory P. Lynch; and for Surviving Family Members by Robert A. Free and Katrin E. Frank.

    142

    [2] To be sure, this acknowledgment did not go far enough, because it overlooked the significance of the word "legitimate," which is most naturally understood to create an objective, federal standard for appropriate medical uses. See Mississippi Band of Choctaw Indians v. Holyfield, 490 U.S. 30, 43 (1989) ("We start . . . with the general assumption that in the absence of a plain indication to the contrary, . . . Congress when it enacts a statute is not making the application of the federal act dependent on state law" (internal quotation marks omitted)).

    143

    [3] The only place outside 21 U.S.C. § 801 in which the statute uses the phrase "legitimate medical purpose" is in defining the phrase "valid prescription" for purposes of the reporting requirements that apply to mail orders of regulated substances. See § 830(b)(3)(A)(ii). The Regulation did not "parrot" this statutory section, because the Regulation was adopted in 1971 and the statutory language was added in 2000. See Brief for Petitioners 17 (citing the Children's Health Act of 2000, § 3652, 114 Stat. 1239, 21 U.S.C. § 830(b)(3)). But even if the statutory language had predated the Regulation, there would be no "parroting" of that phrase. In using the word "prescription" without definition in the much more critical § 829, Congress left the task of resolving any ambiguity in that word, used in that context, to the relevant executive officer. That the officer did so by deeming relevant a technically inapplicable statutory definition contained elsewhere in the statute does not make him a parrot. He has given to the statutory text a meaning it did not explicitly—and perhaps even not necessarily—contain.

    144

    [4] The Court concludes that "[e]ven if `control' in § 821 were understood to signify something other than its statutory definition, it would not support the Interpretive Rule." Ante, at 260. That conclusion rests upon a misidentification of the text that the Attorney General, pursuant to his "control" authority, is interpreting. No one argues that the word "control" in § 821 gives the Attorney General "authority to define diversion based on his view of legitimate medical practice," ibid. Rather, that word authorizes the Attorney General to interpret (among other things) the "prescription" requirement of § 829. The question then becomes whether the phrase "legitimate medical purpose" (which all agree is included in "prescription") is at least open to the interpretation announced in the Directive. See Chevron U.S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 843 (1984). And of course it is—as the Court effectively concedes two pages earlier: "All would agree, we should think, that the statutory phrase `legitimate medical purpose' is a generality, susceptible to more precise definition and open to varying constructions, and thus ambiguous in the relevant sense." Ante, at 258 (citing Chevron).

    145

    [5] This phrase appears only in the Regulation and not in the relevant section of the statute. But as pointed out earlier, the Court does not contest that this is the most reasonable interpretation of the section— regarding it, indeed, as a mere "parroting" of the statute.

    146

    [6] Title 21 U.S.C. § 903 reads, in relevant part, as follows: "No provision of this subchapter shall be construed as indicating an intent on the part of the Congress to occupy the field in which that provision operates, including criminal penalties, to the exclusion of any State law on the same subject matter . . . unless there is a positive conflict . . . ."

    147

    [7] The other case cited by the Court, FDA v. Brown & Williamson Tobacco Corp., 529 U.S. 120 (2000), is even more obviously inapt. There we relied on the first step of the Chevron analysis to determine that Congress had spoken to the precise issue in question, impliedly repealing the grant of jurisdiction on which the Food and Drug Administration relied. 529 U.S., at 160-161. Here, Congress has not expressly or impliedly authorized the practice of assisted suicide, or indeed "spoken directly" to the subject in any way beyond the text of the CSA.

    148

    [8] The majority does not expressly address whether the ingestion of a quantity of drugs that is sufficient to cause death has an "abnormal effec[t] on the nervous system," ante, at 273, though it implicitly rejects such a conclusion.

    149

    [9] Notably, respondents have not seriously pressed a constitutional claim here, conceding at oral argument that their "point is not necessarily that [the CSA] would be unconstitutional." Tr. of Oral Arg. 44. In any event, to the extent respondents do present a constitutional claim, they do so solely within the framework of Raich. Framed in this manner, the claim must fail. The respondents in Raich were "local growers and users of state-authorized, medical marijuana," who stood "outside the interstate drug market" and possessed "`medicinal marijuana . . . not intended for . . . the stream of commerce.'" 545 U.S., at 62, 72 (THOMAS, J., dissenting). Here, by contrast, the respondent-physicians are active participants in the interstate controlled substances market, and the drugs they prescribe for assisting suicide have likely traveled in interstate commerce. If the respondents in Raich could not sustain a constitutional claim, then a fortiori respondents here cannot sustain one. Respondents' acceptance of Raich forecloses their constitutional challenge.

  • 6 National Cable & Telecommunications Assn. v. Brand X Internet Services

    1

    545 U.S. 967 (2005)

    2
    NATIONAL CABLE & TELECOMMUNICATIONS ASSOCIATION ET AL.
    v.
    BRAND X INTERNET SERVICES ET AL.

    No. 04-277.

    3

    Supreme Court of United States.

    Argued March 29, 2005.
    Decided June 27, 2005.[1]

    4

    [972] Paul T. Cappuccio argued the cause for petitioners in No. 04-277. With him on the briefs were Howard J. Symons, Tara M. Corvo, Paul Glist, John D. Seiver, David E. Mills, Daniel L. Brenner, Neal M. Goldberg, Michael S. Schooler, Edward J. Weiss, and Henk Brands.

    5

    Deputy Solicitor General Hungar argued the cause for federal petitioners in No. 04-281. With him on the briefs were Acting Solicitor General Clement, Assistant Attorney [973] General Pate, Deputy Assistant Attorney General Delrahim, James A. Feldman, Catherine G. O'Sullivan, Nancy C. Garrison, John A. Rogovin, Austin C. Schlick, Daniel M. Armstrong, Jacob M. Lewis, and Nandan M. Joshi.

    6

    Thomas C. Goldstein argued the cause for respondents in both cases. With him on the brief were Amy Howe, John W. Butler, Earl W. Comstock, Alison B. Macdonald, Harvey L. Reiter, Matthew J. Verschelden, and Andrew Jay Schwartzman. William H. Sorrell, Attorney General of Vermont, David Borsykowsky, Assistant Attorney General, and Ellen S. LeVine filed a brief in both cases for respondents State of Vermont et al. Michael K. Kellogg, Sean A. Lev, and James G. Harralson filed a brief in both cases for respondents BellSouth et al. Andrew G. McBride, Eve Klindera Reed, William P. Barr, Michael E. Glover, Edward Shakin, and John P. Frantz filed a brief in both cases for respondents Verizon Telephone Companies et al. Mark D. Schneider, Marc A. Goldman, and Jeffrey A. Rackow filed a brief in both cases for respondent MCI, Inc.[2]

    7
    JUSTICE THOMAS delivered the opinion of the Court.
    8

    Title II of the Communications Act of 1934, 48 Stat. 1064, as amended, 47 U. S. C. § 151 et seq., subjects all providers of "telecommunications servic[e]" to mandatory common-carrier regulation, § 153(44). In the order under review, the [974] Federal Communications Commission concluded that cable companies that sell broadband Internet service do not provide "telecommunications servic[e]" as the Communications Act defines that term, and hence are exempt from mandatory common-carrier regulation under Title II. We must decide whether that conclusion is a lawful construction of the Communications Act under Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837 (1984), and the Administrative Procedure Act, 5 U. S. C. § 551 et seq. We hold that it is.

    9
    I
    10

    The traditional means by which consumers in the United States access the network of interconnected computers that make up the Internet is through "dial-up" connections provided over local telephone facilities. See 345 F. 3d 1120, 1123-1124 (CA9 2003) (cases below); In re Inquiry Concerning High-Speed Access to the Internet Over Cable and Other Facilities, 17 FCC Rcd. 4798, 4802-4803, ¶ 9 (2002) (hereinafter Declaratory Ruling). Using these connections, consumers access the Internet by making calls with computer modems through the telephone wires owned by local phone companies. See Verizon Communications Inc. v. FCC, 535 U. S. 467, 489-490 (2002) (describing the physical structure of a local telephone exchange). Internet service providers (ISPs), in turn, link those calls to the Internet network, not only by providing a physical connection, but also by offering consumers the ability to translate raw Internet data into information they may both view on their personal computers and transmit to other computers connected to the Internet. See In re Federal-State Joint Board on Universal Service, 13 FCC Rcd. 11501, 11531, ¶ 63 (1998) (hereinafter Universal Service Report or Report); P. Huber, M. Kellogg, & J. Thorne, Federal Telecommunications Law 988 (2d ed. 1999) (hereinafter Huber); 345 F. 3d, at 1123-1124. Technological limitations of local telephone wires, however, retard the speed at which data from the Internet may be transmitted [975] through end users' dial-up connections. Dial-up connections are therefore known as "narrowband," or slower speed, connections.

    11

    "Broadband" Internet service, by contrast, transmits data at much higher speeds. There are two principal kinds of broadband Internet service: cable modem service and Digital Subscriber Line (DSL) service. Cable modem service transmits data between the Internet and users' computers via the network of television cable lines owned by cable companies. See id., at 1124. DSL service provides high-speed access using the local telephone wires owned by local telephone companies. See WorldCom, Inc. v. FCC, 246 F. 3d 690, 692 (CADC 2001) (describing DSL technology). Cable companies and telephone companies can either provide Internet access directly to consumers, thus acting as ISPs themselves, or can lease their transmission facilities to independent ISPs that then use the facilities to provide consumers with Internet access. Other ways of transmitting high-speed Internet data into homes, including terrestrial and satellite-based wireless networks, are also emerging. Declaratory Ruling 4802, ¶ 6.

    12
    II
    13

    At issue in these cases is the proper regulatory classification under the Communications Act of broadband cable Internet service. The Act, as amended by the Telecommunications Act of 1996, 110 Stat. 56, defines two categories of regulated entities relevant to these cases: telecommunications carriers and information-service providers. The Act regulates telecommunications carriers, but not information service providers, as common carriers. Telecommunications carriers, for example, must charge just and reasonable, nondiscriminatory rates to their customers, 47 U. S. C. §§ 201-209, design their systems so that other carriers can interconnect with their communications networks, § 251(a)(1), and contribute to the federal "universal service" fund, § 254(d). [976] These provisions are mandatory, but the Commission must forbear from applying them if it determines that the public interest requires it. §§ 160(a), (b). Information-service providers, by contrast, are not subject to mandatory common-carrier regulation under Title II, though the Commission has jurisdiction to impose additional regulatory obligations under its Title I ancillary jurisdiction to regulate interstate and foreign communications, see §§ 151-161.

    14

    These two statutory classifications originated in the late 1970's, as the Commission developed rules to regulate data-processing services offered over telephone wires. That regime, the "Computer II" rules, distinguished between "basic" service (like telephone service) and "enhanced" service (computer-processing service offered over telephone lines). In re Amendment of Section 64.702 of the Commission's Rules and Regulations (Second Computer Inquiry), 77 F. C. C. 2d 384, 417-423, ¶¶ 86-101 (1980) (hereinafter Computer II Order). The Computer II rules defined both basic and enhanced services by reference to how the consumer perceives the service being offered.

    15

    In particular, the Commission defined "basic service" as "a pure transmission capability over a communications path that is virtually transparent in terms of its interaction with customer supplied information." Id., at 420, ¶ 96. By "pure" or "transparent" transmission, the Commission meant a communications path that enabled the consumer to transmit an ordinary-language message to another point, with no computer processing or storage of the information, other than the processing or storage needed to convert the message into electronic form and then back into ordinary language for purposes of transmitting it over the network— such as via a telephone or a facsimile. Id., at 419-420, ¶¶ 94-95. Basic service was subject to common-carrier regulation. Id., at 428, ¶ 114.

    16

    "[E]nhanced service," however, was service in which "computer processing applications [were] used to act on the [977] content, code, protocol, and other aspects of the subscriber's information," such as voice and data storage services, id., at 420-421, ¶ 97, as well as "protocol conversion" (i. e., ability to communicate between networks that employ different data-transmission formats), id., at 421-422, ¶ 99. By contrast to basic service, the Commission decided not to subject providers of enhanced service, even enhanced service offered via transmission wires, to Title II common-carrier regulation. Id., at 428-432, ¶¶ 115-123. The Commission explained that it was unwise to subject enhanced service to common-carrier regulation given the "fast-moving, competitive market" in which they were offered. Id., at 434, ¶ 129.

    17

    The definitions of the terms "telecommunications service" and "information service" established by the 1996 Act are similar to the Computer II basic- and enhanced-service classifications. "Telecommunications service"—the analog to basic service—is "the offering of telecommunications for a fee directly to the public . . . regardless of the facilities used." 47 U. S. C. § 153(46). "Telecommunications" is "the transmission, between or among points specified by the user, of information of the user's choosing, without change in the form or content of the information as sent and received." § 153(43). "Telecommunications carrier[s]"—those subjected to mandatory Title II common-carrier regulation—are defined as "provider[s] of telecommunications services." § 153(44). And "information service"—the analog to enhanced service—is "the offering of a capability for generating, acquiring, storing, transforming, processing, retrieving, utilizing, or making available information via telecommunications...." § 153(20).

    18

    In September 2000, the Commission initiated a rulemaking proceeding to, among other things, apply these classifications to cable companies that offer broadband Internet service directly to consumers. In March 2002, that rulemaking culminated in the Declaratory Ruling under review in these cases. In the Declaratory Ruling, the Commission concluded [978] that broadband Internet service provided by cable companies is an "information service" but not a "telecommunications service" under the Act, and therefore not subject to mandatory Title II common-carrier regulation. In support of this conclusion, the Commission relied heavily on its Universal Service Report. See Declaratory Ruling 4821-4822, ¶¶ 36-37 (citing Universal Service Report). The Universal Service Report classified "non-facilities-based" ISPs— those that do not own the transmission facilities they use to connect the end user to the Internet—solely as information-service providers. See Universal Service Report 11533, ¶ 67. Unlike those ISPs, cable companies own the cable lines they use to provide Internet access. Nevertheless, in the Declaratory Ruling, the Commission found no basis in the statutory definitions for treating cable companies differently from non-facilities-based ISPs: Both offer "a single, integrated service that enables the subscriber to utilize Internet access service . . . and to realize the benefits of a comprehensive service offering." Declaratory Ruling 4823, ¶ 38. Because Internet access provides a capability for manipulating and storing information, the Commission concluded that it was an information service. Ibid.

    19

    The integrated nature of Internet access and the high-speed wire used to provide Internet access led the Commission to conclude that cable companies providing Internet access are not telecommunications providers. This conclusion, the Commission reasoned, followed from the logic of the Universal Service Report. The Report had concluded that, though Internet service "involves data transport elements" because "an Internet access provider must enable the movement of information between customers' own computers and distant computers with which those customers seek to interact," it also "offers end users information-service capabilities inextricably intertwined with data transport." Universal Service Report 11539-11540, ¶ 80. ISPs, therefore, were not "offering . . . telecommunications . . . directly to the public," [979] § 153(46), and so were not properly classified as telecommunications carriers, see id., at 11540, ¶ 81. In other words, the Commission reasoned that consumers use their cable modems not to transmit information "transparently," such as by using a telephone, but instead to obtain Internet access.

    20

    The Commission applied this same reasoning to cable companies offering broadband Internet access. Its logic was that, like non-facilities-based ISPs, cable companies do not "offe[r] telecommunications service to the end user, but rather . . . merely us[e] telecommunications to provide end users with cable modem service." Declaratory Ruling 4824, ¶ 41. Though the Commission declined to apply mandatory Title II common-carrier regulation to cable companies, it invited comment on whether under its Title I jurisdiction it should require cable companies to offer other ISPs access to their facilities on common-carrier terms. Id., at 4839, ¶ 72. Numerous parties petitioned for judicial review, challenging the Commission's conclusion that cable modem service was not telecommunications service. By judicial lottery, the Court of Appeals for the Ninth Circuit was selected as the venue for the challenge.

    21

    The Court of Appeals granted the petitions in part, vacated the Declaratory Ruling in part, and remanded to the Commission for further proceedings. In particular, the Court of Appeals vacated the ruling to the extent it concluded that cable modem service was not "telecommunications service" under the Communications Act. It held that the Commission could not permissibly construe the Communications Act to exempt cable companies providing Internet service from Title II regulation. See 345 F. 3d, at 1132. Rather than analyzing the permissibility of that construction under the deferential framework of Chevron, 467 U. S. 837, however, the Court of Appeals grounded its holding in the stare decisis effect of AT&T; Corp. v. Portland, 216 F. 3d 871 (CA9 2000). See 345 F. 3d, at 1128-1132. Portland held that cable modem service was a "telecommunications service," [980] though the court in that case was not reviewing an administrative proceeding and the Commission was not a party to the case. See 216 F. 3d, at 877-880. Nevertheless, Portland's holding, the Court of Appeals reasoned, overrode the contrary interpretation reached by the Commission in the Declaratory Ruling. See 345 F. 3d, at 1130-1131.

    22

    We granted certiorari to settle the important questions of federal law that these cases present. 543 U. S. 1018 (2004).

    23
    III
    24

    We first consider whether we should apply Chevron's framework to the Commission's interpretation of the term "telecommunications service." We conclude that we should. We also conclude that the Court of Appeals should have done the same, instead of following the contrary construction it adopted in Portland.

    25
    A
    26

    In Chevron, this Court held that ambiguities in statutes within an agency's jurisdiction to administer are delegations of authority to the agency to fill the statutory gap in reasonable fashion. Filling these gaps, the Court explained, involves difficult policy choices that agencies are better equipped to make than courts. 467 U. S., at 865-866. If a statute is ambiguous, and if the implementing agency's construction is reasonable, Chevron requires a federal court to accept the agency's construction of the statute, even if the agency's reading differs from what the court believes is the best statutory interpretation. Id., at 843-844, and n. 11.

    27

    The Chevron framework governs our review of the Commission's construction. Congress has delegated to the Commission the authority to "execute and enforce" the Communications Act, § 151, and to "prescribe such rules and regulations as may be necessary in the public interest to carry out the provisions" of the Act, § 201(b); AT&T; Corp. v. Iowa Utilities Bd., 525 U. S. 366, 377-378 (1999). These provisions give the Commission the authority to promulgate [981] binding legal rules; the Commission issued the order under review in the exercise of that authority; and no one questions that the order is within the Commission's jurisdiction. See Household Credit Services, Inc. v. Pfennig, 541 U. S. 232, 238-239 (2004); United States v. Mead Corp., 533 U. S. 218, 231-234 (2001); Christensen v. Harris County, 529 U. S. 576, 586-588 (2000). Hence, as we have in the past, we apply the Chevron framework to the Commission's interpretation of the Communications Act. See National Cable & Telecommunications Assn., Inc. v. Gulf Power Co., 534 U. S. 327, 333-339 (2002); Verizon, 535 U. S., at 501-502.

    28

    Some of the respondents dispute this conclusion, on the ground that the Commission's interpretation is inconsistent with its past practice. We reject this argument. Agency inconsistency is not a basis for declining to analyze the agency's interpretation under the Chevron framework. Un-explained inconsistency is, at most, a reason for holding an interpretation to be an arbitrary and capricious change from agency practice under the Administrative Procedure Act. See Motor Vehicle Mfrs. Assn. of United States, Inc. v. State Farm Mut. Automobile Ins. Co., 463 U. S. 29, 46-57 (1983). For if the agency adequately explains the reasons for a reversal of policy, "change is not invalidating, since the whole point of Chevron is to leave the discretion provided by the ambiguities of a statute with the implementing agency." Smiley v. Citibank (South Dakota), N. A., 517 U. S. 735, 742 (1996); see also Rust v. Sullivan, 500 U. S. 173, 186-187 (1991); Barnhart v. Walton, 535 U. S. 212, 226 (2002) (SCALIA, J., concurring in part and concurring in judgment). "An initial agency interpretation is not instantly carved in stone. On the contrary, the agency ... must consider varying interpretations and the wisdom of its policy on a continuing basis," Chevron, supra, at 863-864, for example, in response to changed factual circumstances, or a change in administrations, see State Farm, supra, at 59 (REHNQUIST, J., concurring in part and dissenting in part). That is no doubt why [982] in Chevron itself, this Court deferred to an agency interpretation that was a recent reversal of agency policy. See 467 U. S., at 857-858. We therefore have no difficulty concluding that Chevron applies.

    29
    B
    30

    The Court of Appeals declined to apply Chevron because it thought the Commission's interpretation of the Communications Act foreclosed by the conflicting construction of the Act it had adopted in Portland. See 345 F. 3d, at 1127-1132. It based that holding on the assumption that Portland's construction overrode the Commission's, regardless of whether Portland had held the statute to be unambiguous. 345 F. 3d, at 1131. That reasoning was incorrect.

    31

    A court's prior judicial construction of a statute trumps an agency construction otherwise entitled to Chevron deference only if the prior court decision holds that its construction follows from the unambiguous terms of the statute and thus leaves no room for agency discretion. This principle follows from Chevron itself. Chevron established a "presumption that Congress, when it left ambiguity in a statute meant for implementation by an agency, understood that the ambiguity would be resolved, first and foremost, by the agency, and desired the agency (rather than the courts) to possess whatever degree of discretion the ambiguity allows." Smiley, supra, at 740-741. Yet allowing a judicial precedent to foreclose an agency from interpreting an ambiguous statute, as the Court of Appeals assumed it could, would allow a court's interpretation to override an agency's. Chevron's premise is that it is for agencies, not courts, to fill statutory gaps. See 467 U. S., at 843-844, and n. 11. The better rule is to hold judicial interpretations contained in precedents to the same demanding Chevron step one standard that applies if the court is reviewing the agency's construction on a blank slate: Only a judicial precedent holding that the statute [983] unambiguously forecloses the agency's interpretation, and therefore contains no gap for the agency to fill, displaces a conflicting agency construction.

    32

    A contrary rule would produce anomalous results. It would mean that whether an agency's interpretation of an ambiguous statute is entitled to Chevron deference would turn on the order in which the interpretations issue: If the court's construction came first, its construction would prevail, whereas if the agency's came first, the agency's construction would command Chevron deference. Yet whether Congress has delegated to an agency the authority to interpret a statute does not depend on the order in which the judicial and administrative constructions occur. The Court of Appeals' rule, moreover, would "lead to the ossification of large portions of our statutory law," Mead, 533 U. S., at 247 (Scalia, J., dissenting), by precluding agencies from revising unwise judicial constructions of ambiguous statutes. Neither Chevron nor the doctrine of stare decisis requires these haphazard results.

    33

    The dissent answers that allowing an agency to override what a court believes to be the best interpretation of a statute makes "judicial decisions subject to reversal by executive officers." Post, at 1016 (opinion of SCALIA, J.). It does not. Since Chevron teaches that a court's opinion as to the best reading of an ambiguous statute an agency is charged with administering is not authoritative, the agency's decision to construe that statute differently from a court does not say that the court's holding was legally wrong. Instead, the agency may, consistent with the court's holding, choose a different construction, since the agency remains the authoritative interpreter (within the limits of reason) of such statutes. In all other respects, the court's prior ruling remains binding law (for example, as to agency interpretations to which Chevron is inapplicable). The precedent has not been "reversed" by the agency, any more than a federal court's interpretation of a State's law can be said to have been "reversed" by a [984] state court that adopts a conflicting (yet authoritative) interpretation of state law.

    34

    The Court of Appeals derived a contrary rule from a mistaken reading of this Court's decisions. It read Neal v. United States, 516 U. S. 284 (1996), to establish that a prior judicial construction of a statute categorically controls an agency's contrary construction. 345 F. 3d, at 1131-1132; see also post, at 1016, n. 11 (SCALIA, J., dissenting). Neal established no such proposition. Neal declined to defer to a construction adopted by the United States Sentencing Commission that conflicted with one the Court previously had adopted in Chapman v. United States, 500 U. S. 453 (1991). Neal, supra, at 290-295. Chapman, however, had held the relevant statute to be unambiguous. See 500 U. S., at 463 (declining to apply the rule of lenity given the statute's clear language). Thus, Neal established only that a precedent holding a statute to be unambiguous forecloses a contrary agency construction. That limited holding accorded with this Court's prior decisions, which had held that a court's interpretation of a statute trumps an agency's under the doctrine of stare decisis only if the prior court holding "determined a statute's clear meaning." Maislin Industries, U. S., Inc. v. Primary Steel, Inc., 497 U. S. 116, 131 (1990) (emphasis added); see also Lechmere, Inc. v. NLRB, 502 U. S. 527, 536-537 (1992). Those decisions allow a court's prior interpretation of a statute to override an agency's interpretation only if the relevant court decision held the statute unambiguous.

    35

    Against this background, the Court of Appeals erred in refusing to apply Chevron to the Commission's interpretation of the definition of "telecommunications service," 47 U. S. C. § 153(46). Its prior decision in Portland held only that the best reading of § 153(46) was that cable modem service was a "telecommunications service," not that it was the only permissible reading of the statute. See 216 F. 3d, at 877-880. Nothing in Portland held that the Communications [985] Act unambiguously required treating cable Internet providers as telecommunications carriers. Instead, the court noted that it was "not presented with a case involving potential deference to an administrative agency's statutory construction pursuant to the Chevron doctrine," id., at 876; and the court invoked no other rule of construction (such as the rule of lenity) requiring it to conclude that the statute was unambiguous to reach its judgment. Before a judicial construction of a statute, whether contained in a precedent or not, may trump an agency's, the court must hold that the statute unambiguously requires the court's construction. Portland did not do so.

    36

    As the dissent points out, it is not logically necessary for us to reach the question whether the Court of Appeals misapplied Chevron for us to decide whether the Commission acted lawfully. See post, at 1019-1020 (opinion of SCALIA, J.). Nevertheless, it is no "great mystery" why we are reaching the point here. Post, at 1019. There is genuine confusion in the lower courts over the interaction between the Chevron doctrine and stare decisis principles, as the petitioners informed us at the certiorari stage of this litigation. See Pet. for Cert. of Federal Communications Commission et al. in No. 04-281, pp. 19-23; Pet. for Cert. of National Cable & Telecomm. Assn. et al. in No. 04-277, pp. 22-29. The point has been briefed. See Brief for Federal Petitioners 38-44; Brief for Cable-Industry Petitioners 30-36. And not reaching the point could undermine the purpose of our grant of certiorari: to settle authoritatively whether the Commission's Declaratory Ruling is lawful. Were we to uphold the Declaratory Ruling without reaching the Chevron point, the Court of Appeals could once again strike down the Commission's rule based on its Portland decision. Portland (at least arguably) could compel the Court of Appeals once again to reverse the Commission despite our decision, since our conclusion that it is reasonable to read the Communications Act to classify cable modem service solely as an "information [986] service" leaves untouched Portland's holding that the Commission's interpretation is not the best reading of the statute. We have before decided similar questions that were not, strictly speaking, necessary to our disposition. See, e. g., Agostini v. Felton, 521 U. S. 203, 237 (1997) (requiring the Courts of Appeals to adhere to our directly controlling precedents, even those that rest on reasons rejected in other decisions); Roper v. Simmons, 543 U. S. 551, 628-629 (2005) (SCALIA, J., dissenting) (criticizing this Court for not reaching the question whether the Missouri Supreme Court erred by failing to follow directly controlling Supreme Court precedent, though that conclusion was not necessary to the Court's decision). It is prudent for us to do so once again today.

    37
    IV
    38

    We next address whether the Commission's construction of the definition of "telecommunications service," 47 U. S. C. § 153(46), is a permissible reading of the Communications Act under the Chevron framework. Chevron established a familiar two-step procedure for evaluating whether an agency's interpretation of a statute is lawful. At the first step, we ask whether the statute's plain terms "directly addres[s] the precise question at issue." 467 U. S., at 843. If the statute is ambiguous on the point, we defer at step two to the agency's interpretation so long as the construction is "a reasonable policy choice for the agency to make." Id., at 845. The Commission's interpretation is permissible at both steps.

    39
    A
    40

    We first set forth our understanding of the interpretation of the Communications Act that the Commission embraced. The issue before the Commission was whether cable companies providing cable modem service are providing a "telecommunications service" in addition to an "information service."

    41

    [987] The Commission first concluded that cable modem service is an "information service," a conclusion unchallenged here. The Act defines "information service" as "the offering of a capability for generating, acquiring, storing, transforming, processing, retrieving, utilizing, or making available information via telecommunications . . . ." § 153(20). Cable modem service is an information service, the Commission reasoned, because it provides consumers with a comprehensive capability for manipulating information using the Internet via high-speed telecommunications. That service enables users, for example, to browse the World Wide Web, to transfer files from file archives available on the Internet via the "File Transfer Protocol," and to access e-mail and Usenet newsgroups. Declaratory Ruling 4821, ¶ 37; Universal Service Report 11537, ¶ 76. Like other forms of Internet service, cable modem service also gives users access to the Domain Name System (DNS). DNS, among other things, matches the Web page addresses that end users type into their browsers (or "click" on) with the Internet Protocol (IP) addresses[3] of the servers containing the Web pages the users wish to access. Declaratory Ruling 4821-4822, ¶ 37. All of these features, the Commission concluded, were part of the information service that cable companies provide consumers. Id., at 4821-4823, ¶¶ 36-38; see also Universal Service Report 11536-11539, ¶¶ 75-79.

    42

    At the same time, the Commission concluded that cable modem service was not "telecommunications service." "Telecommunications service" is "the offering of telecommunications for a fee directly to the public." 47 U. S. C. § 153(46). "Telecommunications," in turn, is defined as "the transmission, between or among points specified by the user, of information of the user's choosing, without change in the form or content of the information as sent and received." [988] § 153(43). The Commission conceded that, like all information-service providers, cable companies use "telecommunications" to provide consumers with Internet service; cable companies provide such service via the high-speed wire that transmits signals to and from an end user's computer. Declaratory Ruling 4823, ¶ 40. For the Commission, however, the question whether cable broadband Internet providers "offer" telecommunications involved more than whether telecommunications was one necessary component of cable modem service. Instead, whether that service also includes a telecommunications "offering" "turn[ed] on the nature of the functions the end user is offered," id., at 4822, ¶ 38 (emphasis added), for the statutory definition of "telecommunications service" does not "res[t] on the particular types of facilities used," id., at 4821, ¶ 35; see § 153(46) (definition of "telecommunications service" applies "regardless of the facilities used").

    43

    Seen from the consumer's point of view, the Commission concluded, cable modem service is not a telecommunications offering because the consumer uses the high-speed wire always in connection with the information-processing capabilities provided by Internet access, and because the transmission is a necessary component of Internet access: "As provided to the end user the telecommunications is part and parcel of cable modem service and is integral to its other capabilities." Declaratory Ruling 4823, ¶ 39. The wire is used, in other words, to access the World Wide Web, newsgroups, and so forth, rather than "transparently" to transmit and receive ordinary-language messages without computer processing or storage of the message. See supra, at 976 (noting the Computer II notion of "transparent" transmission). The integrated character of this offering led the Commission to conclude that cable modem service is not a "stand-alone," transparent offering of telecommunications. Declaratory Ruling 4823-4825, ¶¶ 41-43.

    44
    [989] B
    45

    This construction passes Chevron's first step. Respondents argue that it does not, on the ground that cable companies providing Internet service necessarily "offe[r]" the underlying telecommunications used to transmit that service. The word "offering" as used in § 153(46), however, does not unambiguously require that result. Instead, "offering" can reasonably be read to mean a "stand-alone" offering of telecommunications, i. e., an offered service that, from the user's perspective, transmits messages unadulterated by computer processing. That conclusion follows not only from the ordinary meaning of the word "offering," but also from the regulatory history of the Communications Act.

    46
    1
    47

    Cable companies in the broadband Internet service business "offe[r]" consumers an information service in the form of Internet access and they do so "via telecommunications," § 153(20), but it does not inexorably follow as a matter of ordinary language that they also "offe[r]" consumers the high-speed data transmission (telecommunications) that is an input used to provide this service, § 153(46). We have held that where a statute's plain terms admit of two or more reasonable ordinary usages, the Commission's choice of one of them is entitled to deference. See Verizon, 535 U. S., at 498 (deferring to the Commission's interpretation of the term "cost" by reference to an alternative linguistic usage defined by what "[a] merchant who is asked about `the cost of providing the goods'" might "reasonably" say); National Railroad Passenger Corporation v. Boston & Maine Corp., 503 U. S. 407, 418 (1992) (agency construction entitled to deference where there were "alternative dictionary definitions of the word" at issue). The term "offe[r]" as used in the definition of telecommunications service, § 153(46), is ambiguous in this way.

    48

    [990] It is common usage to describe what a company "offers" to a consumer as what the consumer perceives to be the integrated finished product, even to the exclusion of discrete components that compose the product, as the dissent concedes. See post, at 1006-1007 (opinion of Scalia, J.). One might well say that a car dealership "offers" cars, but does not "offer" the integrated major inputs that make purchasing the car valuable, such as the engine or the chassis. It would, in fact, be odd to describe a car dealership as "offering" consumers the car's components in addition to the car itself. Even if it is linguistically permissible to say that the car dealership "offers" engines when it offers cars, that shows, at most, that the term "offer," when applied to a commercial transaction, is ambiguous about whether it describes only the offered finished product, or the product's discrete components as well. It does not show that no other usage is permitted.

    49

    The question, then, is whether the transmission component of cable modem service is sufficiently integrated with the finished service to make it reasonable to describe the two as a single, integrated offering. See ibid. We think that they are sufficiently integrated, because "[a] consumer uses the high-speed wire always in connection with the information-processing capabilities provided by Internet access, and because the transmission is a necessary component of Internet access." Supra, at 988. In the telecommunications context, it is at least reasonable to describe companies as not "offering" to consumers each discrete input that is necessary to providing, and is always used in connection with, a finished service. We think it no misuse of language, for example, to say that cable companies providing Internet service do not "offer" consumers DNS, even though DNS is essential to providing Internet access. Declaratory Ruling 4810, n. 74, 4822-4823, ¶ 38. Likewise, a telephone company "offers" consumers a transparent transmission path that conveys an ordinary-language message, not necessarily the data-transmission [991] facilities that also "transmi[t] . . . information of the user's choosing," § 153(43), or other physical elements of the facilities used to provide telephone service, like the trunks and switches, or the copper in the wires. What cable companies providing cable modem service and telephone companies providing telephone service "offer" is Internet service and telephone service respectively—the finished services, though they do so using (or "via") the discrete components composing the end product, including data transmission. Such functionally integrated components need not be described as distinct "offerings."

    50

    In response, the dissent argues that the high-speed transmission component necessary to providing cable modem service is necessarily "offered" with Internet service because cable modem service is like the offering of pizza delivery service together with pizza, and the offering of puppies together with dog leashes. Post, at 1007-1008 (opinion of SCALIA, J.). The dissent's appeal to these analogies only underscores that the term "offer" is ambiguous in the way that we have described. The entire question is whether the products here are functionally integrated (like the components of a car) or functionally separate (like pets and leashes). That question turns not on the language of the Act, but on the factual particulars of how Internet technology works and how it is provided, questions Chevron leaves to the Commission to resolve in the first instance. As the Commission has candidly recognized, "the question may not always be straightforward whether, on the one hand, an entity is providing a single information service with communications and computing components, or, on the other hand, is providing two distinct services, one of which is a telecommunications service." Universal Service Report 11530, ¶ 60. Because the term "offer" can sometimes refer to a single, finished product and sometimes to the "individual components in a package being offered" (depending on whether the components "still possess sufficient identity to be described [992] as separate objects," post, at 1006), the statute fails unambiguously to classify the telecommunications component of cable modem service as a distinct offering. This leaves federal telecommunications policy in this technical and complex area to be set by the Commission, not by warring analogies.

    51

    We also do not share the dissent's certainty that cable modem service is so obviously like pizza delivery service and the combination of dog leashes and dogs that the Commission could not reasonably have thought otherwise. Post, at 1007-1008. For example, unlike the transmission component of Internet service, delivery service and dog leashes are not integral components of the finished products (pizzas and pet dogs). One can pick up a pizza rather than having it delivered, and one can own a dog without buying a leash. By contrast, the Commission reasonably concluded, a consumer cannot purchase Internet service without also purchasing a connection to the Internet and the transmission always occurs in connection with information processing. In any event, we doubt that a statute that, for example, subjected offerors of "delivery" service (such as Federal Express and United Parcel Service) to common-carrier regulation would unambiguously require pizza-delivery companies to offer their delivery services on a common-carrier basis.

    52
    2
    53

    The Commission's traditional distinction between basic and enhanced service, see supra, at 976-977, also supports the conclusion that the Communications Act is ambiguous about whether cable companies "offer" telecommunications with cable modem service. Congress passed the definitions in the Communications Act against the background of this regulatory history, and we may assume that the parallel terms "telecommunications service" and "information service" substantially incorporated their meaning, as the Commission has held. See, e. g., In re Federal-State Joint Board on Universal Service, 12 FCC Rcd. 8776, 9179-9180, ¶ 788 [993] (1997) (noting that the "definition of enhanced services is substantially similar to the definition of information services" and that "all services previously considered `enhanced services' are `information services'"); Commissioner v. Keystone Consol. Industries, Inc., 508 U. S. 152, 159 (1993) (noting presumption that Congress is aware of "settled judicial and administrative interpretation[s]" of terms when it enacts a statute). The regulatory history in at least two respects confirms that the term "telecommunications service" is ambiguous.

    54

    First, in the Computer II Order that established the terms "basic" and "enhanced" services, the Commission defined those terms functionally, based on how the consumer interacts with the provided information, just as the Commission did in the order below. See supra, at 976-977. As we have explained, Internet service is not "transparent in terms of its interaction with customer supplied information," Computer II Order 420, ¶ 96; the transmission occurs in connection with information processing. It was therefore consistent with the statute's terms for the Commission to assume that the parallel term "telecommunications service" in 47 U. S. C. § 153(46) likewise describes a "pure" or "transparent" communications path not necessarily separately present, from the end user's perspective, in an integrated information-service offering.

    55

    The Commission's application of the basic/enhanced-service distinction to non-facilities-based ISPs also supports this conclusion. The Commission has long held that "all those who provide some form of transmission services are not necessarily common carriers." Computer II Order 431, ¶ 122; see also id., at 435, ¶ 132 ("acknowledg[ing] the existence of a communications component" in enhanced-service offerings). For example, the Commission did not subject to common-carrier regulation those service providers that offered enhanced services over telecommunications facilities, but that did not themselves own the underlying facilities— so-called "non-facilities-based" providers. See Universal [994] Service Report 11530, ¶ 60. Examples of these services included database services in which a customer used telecommunications to access information, such as Dow Jones News and Lexis, as well as "value added networks," which lease wires from common carriers and provide transmission as well as protocol-processing service over those wires. See In re Amendment to Sections 64.702 of the Commission's Rules and Regulations (Third Computer Inquiry), 3 FCC Rcd. 1150, 1153, n. 23 (1988); supra, at 977 (explaining protocol conversion). These services "combin[ed] communications and computing components," yet the Commission held that they should "always be deemed enhanced" and therefore not subject to common-carrier regulation. Universal Service Report 11530, ¶ 60. Following this traditional distinction, the Commission in the Universal Service Report classified ISPs that leased rather than owned their transmission facilities as pure information-service providers. Id., at 11540, ¶ 81.

    56

    Respondents' statutory arguments conflict with this regulatory history. They claim that the Communications Act unambiguously classifies as telecommunications carriers all entities that use telecommunications inputs to provide information service. As respondent MCI concedes, this argument would subject to mandatory common-carrier regulation all information-service providers that use telecommunications as an input to provide information service to the public. Brief for Respondent MCI, Inc., 30. For example, it would subject to common-carrier regulation non-facilities-based ISPs that own no transmission facilities. See Universal Service Report 11532-11533, ¶ 66. Those ISPs provide consumers with transmission facilities used to connect to the Internet, see supra, at 974, and so, under respondents' argument, necessarily "offer" telecommunications to consumers. Respondents' position that all such entities are necessarily "offering telecommunications" therefore entails mandatory common-carrier regulation of entities that the Commission [995] never classified as "offerors" of basic transmission service, and therefore common carriers, under the Computer II regime.[4] See Universal Service Report 11540, ¶ 81 (noting past Commission policy); Computer and Communications Industry Assn. v. FCC, 693 F. 2d 198, 209 (CADC 1982) (noting and upholding Commission's Computer II "finding that enhanced services . . . are not common carrier services within the scope of Title II"). We doubt that the parallel term "telecommunications service" unambiguously worked this abrupt shift in Commission policy.

    57

    Respondents' analogy between cable companies that provide cable modem service and facilities-based enhanced-service providers—that is, enhanced-service providers who own the transmission facilities used to provide those services—fares no better. Respondents stress that under the Computer II rules the Commission regulated such providers more heavily than non-facilities-based providers. The Commission required, for example, local telephone companies that provided enhanced services to offer their wires on a common-carrier basis to competing enhanced-service providers. See, e. g., In re Amendment of Sections 64.702 of the Commission's Rules and Regulations (Third Computer Inquiry), 104 F. C. C. 2d 958, 964, ¶ 4 (1986) (hereinafter Computer III Order). Respondents argue that the Communications Act unambiguously requires the same treatment for cable companies because cable companies also own the facilities they use to provide cable modem service (and therefore information service).

    58

    [996] We disagree. We think it improbable that the Communications Act unambiguously freezes in time the Computer II treatment of facilities-based information-service providers. The Act's definition of "telecommunications service" says nothing about imposing more stringent regulatory duties on facilities-based information-service providers. The definition hinges solely on whether the entity "offer[s] telecommunications for a fee directly to the public," 47 U. S. C. § 153(46), though the Act elsewhere subjects facilities-based carriers to stricter regulation, see § 251(c) (imposing various duties on facilities-based local telephone companies). In the Computer II rules, the Commission subjected facilities-based providers to common-carrier duties not because of the nature of the "offering" made by those carriers, but rather because of the concern that local telephone companies would abuse the monopoly power they possessed by virtue of the "bottleneck" local telephone facilities they owned. See Computer II Order 474-475, ¶¶ 229, 231; Computer III Order 968-969, ¶ 12; Verizon, 535 U. S., at 489-490 (describing the naturally monopolistic physical structure of a local telephone exchange). The differential treatment of facilities-based carriers was therefore a function not of the definitions of "enhanced-service" and "basic service," but instead of a choice by the Commission to regulate more stringently, in its discretion, certain entities that provided enhanced service. The Act's definitions, however, parallel the definitions of enhanced and basic service, not the facilities-based grounds on which that policy choice was based, and the Commission remains free to impose special regulatory duties on facilities-based ISPs under its Title I ancillary jurisdiction. In fact, it has invited comment on whether it can and should do so. See supra, at 979.

    59

    In sum, if the Act fails unambiguously to classify nonfacilities-based information-service providers that use telecommunications inputs to provide an information service as "offer[ors]" of "telecommunications," then it also fails unambiguously [997] to classify facilities-based information-service providers as telecommunications-service offerors; the relevant definitions do not distinguish facilities-based and nonfacilities-based carriers. That silence suggests, instead, that the Commission has the discretion to fill the consequent statutory gap.

    60
    C
    61

    We also conclude that the Commission's construction was "a reasonable policy choice for the [Commission] to make" at Chevron's second step. 467 U. S., at 845.

    62

    Respondents argue that the Commission's construction is unreasonable because it allows any communications provider to "evade" common-carrier regulation by the expedient of bundling information service with telecommunications. Respondents argue that under the Commission's construction a telephone company could, for example, offer an information service like voice mail together with telephone service, thereby avoiding common-carrier regulation of its telephone service.

    63

    We need not decide whether a construction that resulted in these consequences would be unreasonable because we do not believe that these results follow from the construction the Commission adopted. As we understand the Declaratory Ruling, the Commission did not say that any telecommunications service that is priced or bundled with an information service is automatically unregulated under Title II. The Commission said that a telecommunications input used to provide an information service that is not "separable from the data-processing capabilities of the service" and is instead "part and parcel of [the information service] and is integral to [the information service's] other capabilities" is not a telecommunications offering. Declaratory Ruling 4823, ¶ 39; see supra, at 988.

    64

    This construction does not leave all information-service offerings exempt from mandatory Title II regulation. "It is plain," for example, that a local telephone company "cannot [998] escape Title II regulation of its residential local exchange service simply by packaging that service with voice mail." Universal Service Report 11530, ¶ 60. That is because a telephone company that packages voice mail with telephone service offers a transparent transmission path—telephone service—that transmits information independent of the information-storage capabilities provided by voice mail. For instance, when a person makes a telephone call, his ability to convey and receive information using the call is only trivially affected by the additional voice-mail capability. Equally, were a telephone company to add a time-of-day announcement that played every time the user picked up his telephone, the "transparent" information transmitted in the ensuing call would be only trivially dependent on the information service the announcement provides. By contrast, the high-speed transmission used to provide cable modem service is a functionally integrated component of that service because it transmits data only in connection with the further processing of information and is necessary to provide Internet service. The Commission's construction therefore was more limited than respondents assume.

    65

    Respondents answer that cable modem service does, in fact, provide "transparent" transmission from the consumer's perspective, but this argument, too, is mistaken. Respondents characterize the "information-service" offering of Internet access as consisting only of access to a cable company's e-mail service, its Web page, and the ability it provides consumers to create a personal Web page. When a consumer goes beyond those offerings and accesses content provided by parties other than the cable company, respondents argue, the consumer uses "pure transmission" no less than a consumer who purchases phone service together with voice mail.

    66

    This argument, we believe, conflicts with the Commission's understanding of the nature of cable modem service, an understanding we find to be reasonable. When an end user [999] accesses a third-party's Web site, the Commission concluded, he is equally using the information service provided by the cable company that offers him Internet access as when he accesses the company's own Web site, its e-mail service, or his personal Web page. For example, as the Commission found below, part of the information service cable companies provide is access to DNS service. See supra, at 987. A user cannot reach a third-party's Web site without DNS, which (among other things) matches the Web site address the end user types into his browser (or "clicks" on with his mouse) with the IP address of the Web page's host server. See P. Albitz & C. Liu, DNS and BIND 10 (4th ed. 2001) (For an Internet user, "DNS is a must. . . . [N]early all of the Internet's network services use DNS. That includes the World Wide Web, electronic mail, remote terminal access, and file transfer"). It is at least reasonable to think of DNS as a "capability for . . . acquiring . . . retrieving, utilizing, or making available" Web site addresses and therefore part of the information service cable companies provide. 47 U. S. C. § 153(20).[5] Similarly, the Internet service provided by cable companies facilitates access to third-party Web pages by offering consumers the ability to store, or "cache," popular content on local computer servers. See Declaratory Ruling 4810, ¶ 17, and n. 76. Cacheing obviates the need for the end user to download anew information from third-party [1000] Web sites each time the consumer attempts to access them, thereby increasing the speed of information retrieval. In other words, subscribers can reach third-party Web sites via "the World Wide Web, and browse their contents, [only] because their service provider offers the `capability for . . . acquiring, [storing] . . . retrieving [and] utilizing . . . information.'" Universal Service Report 11538, ¶ 76 (quoting 47 U. S. C. § 153(20)). "The service that Internet access providers offer to members of the public is Internet access," Universal Service Report 11539, ¶ 79, not a transparent ability (from the end user's perspective) to transmit information. We therefore conclude that the Commission's construction was reasonable.

    67
    V
    68

    Respondent MCI, Inc., urges that the Commission's treatment of cable modem service is inconsistent with its treatment of DSL service, see supra, at 975 (describing DSL service), and therefore is an arbitrary and capricious deviation from agency policy. See 5 U. S. C. § 706(2)(A). MCI points out that when local telephone companies began to offer Internet access through DSL technology in addition to telephone service, the Commission applied its Computer II facilities-based classification to them and required them to make the telephone lines used to transmit DSL service available to competing ISPs on nondiscriminatory, common-carrier terms. See supra, at 996 (describing Computer II facilities-based classification of enhanced-service providers); In re Deployment of Wireline Services Offering Advanced Telecommunications Capability, 13 FCC Rcd. 24011, 24030-24031, ¶¶ 36-37 (1998) (hereinafter Wireline Order) (classifying DSL service as a telecommunications service). MCI claims that the Commission's decision not to regulate cable companies similarly under Title II is inconsistent with its DSL policy.

    69

    We conclude, however, that the Commission provided a reasoned explanation for treating cable modem service differently [1001] from DSL service. As we have already noted, see supra, at 981-982, the Commission is free within the limits of reasoned interpretation to change course if it adequately justifies the change.[6] It has done so here. The traditional reason for its Computer II common-carrier treatment of facilities-based carriers (including DSL carriers), as the Commission explained, was "that the telephone network [was] the primary, if not exclusive, means through which information service providers can gain access to their customers." Declaratory Ruling 4825, ¶ 44 (emphasis in original; internal quotation marks omitted). The Commission applied the same treatment to DSL service based on that history, rather than on an analysis of contemporaneous market conditions. See Wireline Order 24031, ¶ 37 (noting DSL carriers' "continuing obligation" to offer their transmission facilities to competing ISPs on nondiscriminatory terms).

    70

    The Commission in the order under review, by contrast, concluded that changed market conditions warrant different treatment of facilities-based cable companies providing Internet access. Unlike at the time of Computer II, substitute forms of Internet transmission exist today: "[R]esidential high-speed access to the Internet is evolving over multiple electronic platforms, including wireline, cable, terrestrial wireless and satellite." Declaratory Ruling 4802, ¶ 6; see also U. S. Telecom Assn. v. FCC, 290 F. 3d 415, 428 (CADC 2002) (noting Commission findings of "robust competition . . . in the broadband market"). The Commission concluded that "`broadband services should exist in a minimal regulatory environment that promotes investment and innovation in a competitive market.'" Declaratory Ruling 4802, ¶ 5. [1002] This, the Commission reasoned, warranted treating cable companies unlike the facilities-based enhanced-service providers of the past. Id., at 4825, ¶ 44. We find nothing arbitrary about the Commission's providing a fresh analysis of the problem as applied to the cable industry, which it has never subjected to these rules. This is adequate rational justification for the Commission's conclusions.

    71

    Respondents argue, in effect, that the Commission's justification for exempting cable modem service providers from common-carrier regulation applies with similar force to DSL providers. We need not address that argument. The Commission's decision appears to be a first step in an effort to reshape the way the Commission regulates information-service providers; that may be why it has tentatively concluded that DSL service provided by facilities-based telephone companies should also be classified solely as an information service. See In re Appropriate Framework for Broadband Access to the Internet over Wireline Facilities, 17 FCC Rcd. 3019, 3030, ¶ 20 (2002). The Commission need not immediately apply the policy reasoning in the Declaratory Ruling to all types of information-service providers. It apparently has decided to revisit its longstanding Computer II classification of facilities-based information-service providers incrementally. Any inconsistency between the order under review and the Commission's treatment of DSL service can be adequately addressed when the Commission fully reconsiders its treatment of DSL service and when it decides whether, pursuant to its ancillary Title I jurisdiction, to require cable companies to allow independent ISPs access to their facilities. See supra, at 979 and this page. We express no view on those matters. In particular, we express no view on how the Commission should, or lawfully may, classify DSL service.

    72

    * * *

    73

    The questions the Commission resolved in the order under review involve a "subject matter [that] is technical, complex, [1003] and dynamic." Gulf Power, 534 U. S., at 339. The Commission is in a far better position to address these questions than we are. Nothing in the Communications Act or the Administrative Procedure Act makes unlawful the Commission's use of its expert policy judgment to resolve these difficult questions. The judgment of the Court of Appeals is reversed, and the cases are remanded for further proceedings consistent with this opinion.

    74

    It is so ordered.

    75
    JUSTICE STEVENS, concurring.
    76

    While I join the Court's opinion in full, I add this caveat concerning Part III-B, which correctly explains why a court of appeals' interpretation of an ambiguous provision in a regulatory statute does not foreclose a contrary reading by the agency. That explanation would not necessarily be applicable to a decision by this Court that would presumably remove any pre-existing ambiguity.

    77
    JUSTICE BREYER, concurring.
    78

    I join the Court's opinion because I believe that the Federal Communications Commission's decision falls within the scope of its statutorily delegated authority—though perhaps just barely. I write separately because I believe it important to point out that JUSTICE SCALIA, in my view, has wrongly characterized the Court's opinion in United States v. Mead Corp., 533 U. S. 218 (2001). He states that the Court held in Mead that "some unspecified degree of formal process" before the agency "was required" for courts to accord the agency's decision deference under Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837 (1984). Post, at 1015 (dissenting opinion); see also ibid. (formal process is "at least the only safe harbor").

    79

    JUSTICE SCALIA has correctly characterized the way in which he, in dissent, characterized the Court's Mead opinion. 533 U. S., at 245-246. But the Court said the opposite. An [1004] agency action qualifies for Chevron deference when Congress has explicitly or implicitly delegated to the agency the authority to "fill" a statutory "gap," including an interpretive gap created through an ambiguity in the language of a statute's provisions. Chevron, supra, at 843-844; Mead, supra, at 226-227. The Court said in Mead that such delegation "may be shown in a variety of ways, as by an agency's power to engage in adjudication or notice-and-comment rulemaking, or by some other indication of a comparable congressional intent." 533 U. S., at 227 (emphasis added). The Court explicitly stated that the absence of notice-and-comment rulemaking did "not decide the case," for the Court has "sometimes found reasons for Chevron deference even when no such administrative formality was required and none was afforded." Id., at 231. And the Court repeated that it "has recognized a variety of indicators that Congress would expect Chevron deference." Id., at 237 (emphasis added).

    80

    It is not surprising that the Court would hold that the existence of a formal rulemaking proceeding is neither a necessary nor a sufficient condition for according Chevron deference to an agency's interpretation of a statute. It is not a necessary condition because an agency might arrive at an authoritative interpretation of a congressional enactment in other ways, including ways that JUSTICE SCALIA mentions. See, e. g., Mead, supra, at 231. It is not a sufficient condition because Congress may have intended not to leave the matter of a particular interpretation up to the agency, irrespective of the procedure the agency uses to arrive at that interpretation, say, where an unusually basic legal question is at issue. Cf. General Dynamics Land Systems, Inc. v. Cline, 540 U. S. 581, 600 (2004) (rejecting agency's answer to question whether age discrimination law forbids discrimination against the relatively young).

    81

    Thus, while I believe JUSTICE SCALIA is right in emphasizing that Chevron deference may be appropriate in the absence [1005] of formal agency proceedings, Mead should not give him cause for concern.

    82
    JUSTICE SCALIA, with whom JUSTICE SOUTER and JUSTICE GINSBURG join as to Part I, dissenting.
    83

    The Federal Communications Commission (FCC or Commission) has once again attempted to concoct "a whole new regime of regulation (or of free-market competition)" under the guise of statutory construction. MCI Telecommunications Corp. v. American Telephone & Telegraph Co., 512 U. S. 218, 234 (1994). Actually, in these cases, it might be more accurate to say the Commission has attempted to establish a whole new regime of non-regulation, which will make for more or less free-market competition, depending upon whose experts are believed. The important fact, however, is that the Commission has chosen to achieve this through an implausible reading of the statute, and has thus exceeded the authority given it by Congress.

    84
    I
    85

    The first sentence of the FCC ruling under review reads as follows: "Cable modem service provides high-speed access to the Internet, as well as many applications or functions that can be used with that access, over cable system facilities." In re Inquiry Concerning High-Speed Access to the Internet Over Cable and Other Facilities, 17 FCC Rcd. 4798, 4799, ¶ 1 (2002) (hereinafter Declaratory Ruling) (emphasis added; footnote omitted). Does this mean that cable companies "offer" high-speed access to the Internet? Surprisingly not, if the Commission and the Court are to be believed.

    86

    It happens that cable-modem service is popular precisely because of the high-speed access it provides, and that, once connected with the Internet, cable-modem subscribers often use Internet applications and functions from providers other than the cable company. Nevertheless, for purposes of classifying [1006] what the cable company does, the Commission (with the Court's approval) puts all the emphasis on the rest of the package (the additional "applications or functions"). It does so by claiming that the cable company does not "offe[r]" its customers high-speed Internet access because it offers that access only in conjunction with particular applications and functions, rather than "separate[ly]," as a "stand-alone offering." Id., at 4802, ¶ 7, 4823, ¶ 40.

    87

    The focus on the term "offer" appropriately derives from the statutory definitions at issue in these cases. Under the Telecommunications Act of 1996, 110 Stat. 59, "`information service'" involves the capacity to generate, store, interact with, or otherwise manipulate "information via telecommunications." 47 U. S. C. § 153(20). In turn, "`telecommunications'" is defined as "the transmission, between or among points specified by the user, of information of the user's choosing, without change in the form or content of the information as sent and received." § 153(43). Finally, "`telecommunications service'" is defined as "the offering of telecommunications for a fee directly to the public . . . regardless of the facilities used." § 153(46). The question here is whether cable-modem-service providers "offe[r] . . . telecommunications for a fee directly to the public." If so, they are subject to Title II regulation as common carriers, like their chief competitors who provide Internet access through other technologies.

    88

    The Court concludes that the word "offer" is ambiguous in the sense that it has "`alternative dictionary definitions'" that might be relevant. Ante, at 989 (quoting National Railroad Passenger Corporation v. Boston & Maine Corp., 503 U. S. 407, 418 (1992)). It seems to me, however, that the analytic problem pertains not really to the meaning of "offer," but to the identity of what is offered. The relevant question is whether the individual components in a package being offered still possess sufficient identity to be described as separate objects of the offer, or whether they have been [1007] so changed by their combination with the other components that it is no longer reasonable to describe them in that way.

    89

    Thus, I agree (to adapt the Court's example, ante, at 990) that it would be odd to say that a car dealer is in the business of selling steel or carpets because the cars he sells include both steel frames and carpeting. Nor does the water company sell hydrogen, nor the pet store water (though dogs and cats are largely water at the molecular level). But what is sometimes true is not, as the Court seems to assume, always true. There are instances in which it is ridiculous to deny that one part of a joint offering is being offered merely because it is not offered on a "`stand-alone'" basis, ante, at 989.

    90

    If, for example, I call up a pizzeria and ask whether they offer delivery, both common sense and common "usage," ante, at 990, would prevent them from answering: "No, we do not offer delivery—but if you order a pizza from us, we'll bake it for you and then bring it to your house." The logical response to this would be something on the order of, "so, you do offer delivery." But our pizza-man may continue to deny the obvious and explain, paraphrasing the FCC and the Court: "No, even though we bring the pizza to your house, we are not actually `offering' you delivery, because the delivery that we provide to our end users is `part and parcel' of our pizzeria-pizza-at-home service and is `integral to its other capabilities.'" Cf. Declaratory Ruling 4823, ¶ 39; ante, at 988, 997-998.[7] Any reasonable customer would conclude at that point that his interlocutor was either crazy or following some too-clever-by-half legal advice.

    91

    In short, for the inputs of a finished service to qualify as the objects of an "offer" (as that term is reasonably understood), it is perhaps a sufficient, but surely not a necessary, condition that the seller offer separately "each discrete input [1008] that is necessary to providing . . . a finished service," ante, at 990. The pet store may have a policy of selling puppies only with leashes, but any customer will say that it does offer puppies—because a leashed puppy is still a puppy, even though it is not offered on a "stand-alone" basis.

    92

    Despite the Court's mighty labors to prove otherwise, ante, at 989-1000, the telecommunications component of cable-modem service retains such ample independent identity that it must be regarded as being on offer—especially when seen from the perspective of the consumer or the end user, which the Court purports to find determinative, ante, at 990, 993, 998, 1000. The Commission's ruling began by noting that cable-modem service provides both "high-speed access to the Internet" and other "applications and functions," Declaratory Ruling 4799, ¶ 1, because that is exactly how any reasonable consumer would perceive it: as consisting of two separate things.

    93

    The consumer's view of the matter is best assessed by asking what other products cable-modem service substitutes for in the marketplace. Broadband Internet service provided by cable companies is one of the three most common forms of Internet service, the other two being dial-up access and broadband Digital Subscriber Line (DSL) service. Ante, at 974-975. In each of the other two, the physical transmission pathway to the Internet is sold—indeed, is legally required to be sold—separately from the Internet functionality. With dial-up access, the physical pathway comes from the telephone company, and the Internet service provider (ISP) provides the functionality.

    94

    "In the case of Internet access, the end user utilizes two different and distinct services. One is the transmission pathway, a telecommunications service that the end user purchases from the telephone company. The second is the Internet access service, which is an enhanced service provided by an ISP. . . . Th[e] functions [provided by the ISP] are separate from the transmission pathway [1009] over which that data travels. The pathway is a regulated telecommunications service; the enhanced service offered over it is not." FCC, Office of Plans and Policy, J. Oxman, The FCC and the Unregulation of the Internet, p. 13 (Working Paper No. 31, July 1999), available at http://www.fcc.gov/Bureaus/OPP/working_papers/oppwp31.pdf (as visited June 24, 2005, and available in Clerk of Court's case file).[8]

    95

    As the Court acknowledges, ante, at 1000, DSL service has been similar to dial-up service in the respect that the physical connection to the Internet must be offered separately from Internet functionality.[9] Thus, customers shopping for dial-up or DSL service will not be able to use the Internet unless they get both someone to provide them with a physical connection and someone to provide them with applications and functions such as e-mail and Web access. It is therefore inevitable that customers will regard the competing cable-modem service as giving them both computing functionality and the physical pipe by which that functionality comes to their computer—both the pizza and the delivery service that nondelivery pizzerias require to be purchased from the cab company.[10]

    96

    [1010] Since the delivery service provided by cable (the broadband connection between the customer's computer and the cable company's computer-processing facilities) is downstream from the computer-processing facilities, there is no question that it merely serves as a conduit for the information services that have already been "assembled" by the cable company in its capacity as ISP. This is relevant because of the statutory distinction between an "information service" and "telecommunications." The former involves the capability of getting, processing, and manipulating information. § 153(20). The latter, by contrast, involves no "change in the form or content of the information as sent and received." § 153(43). When cable-company-assembled information enters the cable for delivery to the subscriber, the information service is already complete. The information has been (as the statute requires) generated, acquired, stored, transformed, processed, retrieved, utilized, or made available. All that remains is for the information in its final, unaltered form, to be delivered (via telecommunications) to the subscriber.

    97

    This reveals the insubstantiality of the fear invoked by both the Commission and the Court: the fear of what will happen to ISPs that do not provide the physical pathway to Internet access, yet still use telecommunications to acquire the pieces necessary to assemble the information that they pass back to their customers. According to this reductio, ante, at 993-995, if cable-modem-service providers are deemed to provide "telecommunications service," then so must all ISPs because they all "use" telecommunications in providing Internet functionality (by connecting to other [1011] parts of the Internet, including Internet backbone providers, for example). In terms of the pizzeria analogy, this is equivalent to saying that, if the pizzeria "offers" delivery, all restaurants "offer" delivery, because the ingredients of the food they serve their customers have come from other places; no matter how their customers get the food (whether by eating it at the restaurant, or by coming to pick it up themselves), they still consume a product for which delivery was a necessary "input." This is nonsense. Concluding that delivery of the finished pizza constitutes an "offer" of delivery does not require the conclusion that the serving of prepared food includes an "offer" of delivery. And that analogy does not even do the point justice, since "`telecommunications service'" is defined as "the offering of telecommunications for a fee directly to the public." § 153(46) (emphasis added). The ISPs' use of telecommunications in their processing of information is not offered directly to the public.

    98

    The "regulatory history" on which the Court depends so much, ante, at 992-997, provides another reason why common-carrier regulation of all ISPs is not a worry. Under its Computer Inquiry rules, which foreshadowed the definitions of "information" and "telecommunications" services, ante, at 976-977, the Commission forbore from regulating as common carriers "value-added networks"—non-facilities-based providers who leased basic services from common carriers and bundled them with enhanced services; it said that they, unlike facilities-based providers, would be deemed to provide only enhanced services, ante, at 993-994.[11] That [1012] same result can be achieved today under the Commission's statutory authority to forbear from imposing most Title II regulations. § 160. In fact, the statutory criteria for forbearance—which include what is "just and reasonable," "necessary for the protection of consumers," and "consistent with the public interest," §§ 160(a)(1), (2), (3)—correspond well with the kinds of policy reasons the Commission has invoked to justify its peculiar construction of "telecommunications service" to exclude cable-modem service.

    99

    The Court also puts great stock in its conclusion that cable-modem subscribers cannot avoid using information services provided by the cable company in its ISP capacity, even when they only click-through to other ISPs. Ante, at 998-1000. For, even if a cable-modem subscriber uses e-mail from another ISP, designates some page not provided by the cable company as his home page, and takes advantage of none of the other standard applications and functions provided by the cable company, he will still be using the cable company's Domain Name System (DNS) server and, when he goes to popular Web pages, perhaps versions of them that are stored in the cable company's cache. This argument suffers from at least two problems. First, in the context of telephone services, the Court recognizes a de minimis exception to contamination of a telecommunications service by an information service. Ante, at 997-998. A similar exception would seem to apply to the functions in question here. DNS, in particular, is scarcely more than routing information, [1013] which is expressly excluded from the definition of "information service." § 153(20).[12] Second, it is apparently possible to sell a telecommunications service separately from, although in conjunction with, ISP-like services; that is precisely what happens in the DSL context, and the Commission does not contest that it could be done in the context of cable. The only impediment appears to be the Commission's failure to require from cable companies the unbundling that it required of facilities-based providers under its Computer Inquiry.

    100

    Finally, I must note that, notwithstanding the Commission's self-congratulatory paean to its deregulatory largesse, e. g., Brief for Federal Petitioners 29-32, it concluded the Declaratory Ruling by asking, as the Court paraphrases, "whether under its Title I jurisdiction [the Commission] should require cable companies to offer other ISPs access to their facilities on common-carrier terms." Ante, at 979; see also Reply Brief for Federal Petitioners 9; Tr. of Oral Arg. 17. In other words, what the Commission hath given, the Commission may well take away—unless it doesn't. This is a wonderful illustration of how an experienced agency can (with some assistance from credulous courts) turn statutory constraints into bureaucratic discretions. The main source of the Commission's regulatory authority over common carriers is Title II, but the Commission has rendered that inapplicable in this instance by concluding that the definition of "telecommunications service" is ambiguous and does not (in [1014] its current view) apply to cable-modem service. It contemplates, however, altering that (unnecessary) outcome, not by changing the law (i. e., its construction of the Title II definitions), but by reserving the right to change the facts. Under its undefined and sparingly used "ancillary" powers, the Commission might conclude that it can order cable companies to "unbundle" the telecommunications component of cable-modem service.[13] And presto, Title II will then apply to them, because they will finally be "offering" telecommunications service! Of course, the Commission will still have the statutory power to forbear from regulating them under § 160 (which it has already tentatively concluded it would do, Declaratory Ruling 4847-4848, ¶¶ 94-95). Such Möbius-strip reasoning mocks the principle that the statute constrains the agency in any meaningful way.

    101

    After all is said and done, after all the regulatory cant has been translated, and the smoke of agency expertise blown away, it remains perfectly clear that someone who sells cable-modem service is "offering" telecommunications. For that simple reason set forth in the statute, I would affirm the Court of Appeals.

    102
    II
    103

    In Part III-B of its opinion, the Court continues the administrative-law improvisation project it began four years ago in United States v. Mead Corp., 533 U. S. 218 (2001). To the extent it set forth a comprehensible rule,[14] Mead drastically [1015] limited the categories of agency action that would qualify for deference under Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837 (1984). For example, the position taken by an agency before the Supreme Court, with full approval of the agency head, would not qualify. Rather, some unspecified degree of formal process was required—or was at least the only safe harbor. See Mead, supra, at 245-246 (SCALIA, J., dissenting).[15]

    104

    This meant that many more issues appropriate for agency determination would reach the courts without benefit of an agency position entitled to Chevron deference, requiring the courts to rule on these issues de novo.[16] As I pointed out in [1016] dissent, this in turn meant (under the law as it was understood until today)[17] that many statutory ambiguities that might be resolved in varying fashions by successive agency administrations would be resolved finally, conclusively, and forever, by federal judges—producing an "ossification of large portions of our statutory law," 533 U. S., at 247. The Court today moves to solve this problem of its own creation by inventing yet another breathtaking novelty: judicial decisions subject to reversal by executive officers.

    105

    Imagine the following sequence of events: FCC action is challenged as ultra vires under the governing statute; the litigation reaches all the way to the Supreme Court of the United States. The Solicitor General sets forth the FCC's official position (approved by the Commission) regarding interpretation of the statute. Applying Mead, however, the Court denies the agency position Chevron deference, finds that the best interpretation of the statute contradicts the agency's position, and holds the challenged agency action unlawful. The agency promptly conducts a rulemaking, and [1017] adopts a rule that comports with its earlier position—in effect disagreeing with the Supreme Court concerning the best interpretation of the statute. According to today's opinion, the agency is thereupon free to take the action that the Supreme Court found unlawful.

    106

    This is not only bizarre. It is probably unconstitutional. As we held in Chicago & Southern Air Lines, Inc. v. Waterman S. S. Corp., 333 U. S. 103 (1948), Article III courts do not sit to render decisions that can be reversed or ignored by executive officers. In that case, the Court of Appeals had determined it had jurisdiction to review an order of the Civil Aeronautics Board awarding an overseas air route. By statute such orders were subject to Presidential approval and the order in question had in fact been approved by the President. Id., at 110-111. In order to avoid any conflict with the President's foreign-affairs powers, the Court of Appeals concluded that it would review the board's action "as a regulatory agent of Congress," and the results of that review would remain subject to approval or disapproval by the President. Id., at 112-113. As I noted in my Mead dissent, 533 U. S., at 248, the Court bristled at the suggestion: "Judgments within the powers vested in courts by the Judiciary Article of the Constitution may not lawfully be revised, overturned or refused faith and credit by another Department of Government." Waterman, supra, at 113. That is what today's decision effectively allows. Even when the agency itself is party to the case in which the Court construes a statute, the agency will be able to disregard that construction and seek Chevron deference for its contrary construction the next time around.[18]

    107

    [1018] Of course, like Mead itself, today's novelty in belated remediation of Mead creates many uncertainties to bedevil the lower courts. A court's interpretation is conclusive, the Court says, only if it holds that interpretation to be "the only permissible reading of the statute," and not if it merely holds it to be "the best reading." Ante, at 984. Does this mean that in future statutory-construction cases involving agency-administered statutes courts must specify (presumably in dictum) which of the two they are holding? And what of the many cases decided in the past, before this dictum's requirement was established? Apparently, silence on the point means that the court's decision is subject to agency reversal: "Before a judicial construction of a statute, whether contained in a precedent or not, may trump an agency's, the court must hold that the statute unambiguously requires the court's construction."[19] Ante, at 985. (I have not made, and as far as I know the Court has not made, any calculation of how many hundreds of past statutory decisions are now agency-reversible because of failure to include an "unambiguous" finding. I suspect the number is very large.) How much extra work will it entail for each court confronted with an agency-administered statute to determine whether it has reached, not only the right ("best") result, but "the only permissible" result? Is the standard for "unambiguous" under the Court's new agency-reversal rule the same as the standard for "unambiguous" under step one of Chevron? (If so, [1019] of course, every case that reaches step two of Chevron will be agency-reversible.) Does the "unambiguous" dictum produce stare decisis effect even when a court is affirming, rather than reversing, agency action—so that in the future the agency must adhere to that affirmed interpretation? If so, does the victorious agency have the right to appeal a Court of Appeals judgment in its favor, on the ground that the text in question is in fact not (as the Court of Appeals held) unambiguous, so the agency should be able to change its view in the future?

    108

    It is indeed a wonderful new world that the Court creates, one full of promise for administrative-law professors in need of tenure articles and, of course, for litigators.[20] I would adhere to what has been the rule in the past: When a court interprets a statute without Chevron deference to agency views, its interpretation (whether or not asserted to rest upon an unambiguous text) is the law. I might add that it is a great mystery why any of this is relevant here. Whatever the stare decisis effect of AT&T; Corp. v. Portland, 216 F. 3d 871 (CA9 2000), in the Ninth Circuit, it surely does not govern this Court's decision. And—despite the Court's peculiar, self-abnegating suggestion to the contrary, ante, at 985-986—the Ninth Circuit would already be obliged to [1020] abandon Portland's holding in the face of this Court's decision that the Commission's construction of "telecommunications service" is entitled to deference and is reasonable. It is a sadness that the Court should go so far out of its way to make bad law.

    109

    I respectfully dissent.

    110

    [1] Together with No. 04-281, Federal Communications Commission et al. v. Brand X Internet Services et al., also on certiorari to the same court.

    111

    [2] Briefs of amici curiae urging reversal in both cases were filed for the Telecommunications Industry Association by Colleen L. Boothby and Andrew M. Brown; and for the Washington Legal Foundation by Daniel J. Popeo and David Price.

    112

    Briefs of amici curiae urging affirmance in both cases were filed for the State of New Jersey, Board of Public Utilities, by Peter C. Harvey, Attorney General of New Jersey, Andrea M. Silkowitz, Assistant Attorney General, and Kenneth J. Sheehan, Deputy Attorney General; for AARP et al. by Stacy Canan and Michael Schuster; for the American Civil Liberties Union et al. by Steven R. Shapiro, Christopher A. Hansen, Jennifer Stisa Granick, and Marjorie Heins; and for the National Association of Regulatory Utility Commissioners by James Bradford Ramsay.

    113

    [3] IP addresses identify computers on the Internet, enabling data packets transmitted from other computers to reach them. See Universal Service Report 11531, ¶ 62; Huber 985.

    114

    [4] The dissent attempts to escape this consequence of respondents' position by way of an elaborate analogy between ISPs and pizzerias. Post, at 1011 (opinion of SCALIA, J.). This analogy is flawed. A pizzeria "delivers" nothing, but ISPs plainly provide transmission service directly to the public in connection with Internet service. For example, with dial-up service, ISPs process the electronic signal that travels over local telephone wires, and transmit it to the Internet. See supra, at 974-975; Huber 988. The dissent therefore cannot deny that its position logically would require applying presumptively mandatory Title II regulation to all ISPs.

    115

    [5] The dissent claims that access to DNS does not count as use of the information-processing capabilities of Internet service because DNS is "scarcely more than routing information, which is expressly excluded from the definition of `information service.'" Post, at 1012-1013, and n. 6 (opinion of SCALIA, J.). But the definition of information service does not exclude "routing information." Instead, it excludes "any use of any such capability for the management, control, or operation of a telecommunications system or the management of a telecommunications service." 47 U. S. C. § 153(20). The dissent's argument therefore begs the question because it assumes that Internet service is a "telecommunications system" or "service" that DNS manages (a point on which, contrary to the dissent's assertion, post, at 1013, n. 6, we need take no view for purposes of this response).

    116

    [6] Respondents vigorously argue that the Commission's purported inconsistent treatment is a reason for holding the Commission's construction impermissible under Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837 (1984). Any inconsistency bears on whether the Commission has given a reasoned explanation for its current position, not on whether its interpretation is consistent with the statute.

    117

    [7] The myth that the pizzeria does not offer delivery becomes even more difficult to maintain when the pizzeria advertises quick delivery as one of its advantages over competitors. That, of course, is the case with cable broadband.

    118

    [8] See also In re Federal-State Joint Board on Universal Service, 13 FCC Rcd. 11501, 11571-11572, ¶ 145 (1998) (end users "obtain telecommunications service from local exchange carriers, and then use information services provided by their Internet service provider and [Web site operators] in order to access [the Web]").

    119

    [9] In the DSL context, the physical connection is generally resold to the consumer by an ISP that has taken advantage of the telephone company's offer. The consumer knows very well, however, that the physical connection is a necessary component for Internet access which, just as in the dial-up context, is not provided by the ISP.

    120

    [10] The Court contends that this analogy is inapposite because one need not have a pizza delivered, ante, at 992, whereas one must purchase the cable connection in order to use cable's ISP functions. But the ISP functions provided by the cable company can be used without cable delivery— by accessing them from an Internet connection other than cable. The merger of the physical connection and Internet functions in cable's offerings has nothing to do with the "`inextricably intertwined,'" ante, at 978, nature of the two (like a car and its carpet), but is an artificial product of the cable company's marketing decision not to offer the two separately, so that the Commission could (by the Declaratory Ruling under review here) exempt it from common-carrier status.

    121

    [11] The Commission says forbearance cannot explain why value-added networks were not regulated as basic-service providers because it was not given the power to forbear until 1996. Reply Brief for Federal Petitioners 3-4, n. 1. It is true that when the Commission ruled on value-added networks, the statute did not explicitly provide for forbearance—any more than it provided for the categories of basic and enhanced services that the Computer Inquiry rules established, and through which the forbearance was applied. The D. C. Circuit, however, had long since recognized the Commission's discretionary power to "forbear from Title II regulation." Computer and Communications Industry Assn. v. FCC, 693 F. 2d 198, 212 (1982).

    122

    The Commission also says its Computer Inquiry rules should not apply to cable because they were developed in the context of telephone lines. Brief for Federal Petitioners 35-36; see also ante, at 996. But to the extent that the statute imported the Computer Inquiry approach, there is no basis for applying it differently to cable than to telephone lines, since the definition of "telecommunications service" applies "regardless of the facilities used." 47 U. S. C. § 153(46).

    123

    [12] The Court says that invoking this explicit exception from the definition of information services, which applies only to the "management, control, or operation of a telecommunications system or the management of a telecommunications service," § 153(20), begs the question whether cable-modem service includes a telecommunications service, ante, at 999, n. 3. I think not, and cite the exception only to demonstrate that the incidental functions do not prevent cable from including a telecommunications service if it otherwise qualifies. It is rather the Court that begs the question, saying that the exception cannot apply because cable is not a telecommunications service.

    124

    [13] Under the Commission's assumption that cable-modem-service providers are not providing "telecommunications services," there is reason to doubt whether it can use its Title I powers to impose common-carrier-like requirements, since § 153(44) specifically provides that a "telecommunications carrier shall be treated as a common carrier under this chapter only to the extent that it is engaged in providing telecommunications services" (emphasis added), and "this chapter" includes Titles I and II.

    125

    [14] For a description of the confusion Mead has produced, see Vermeule, Mead in the Trenches, 71 Geo. Wash. L. Rev. 347, 361 (2003) (concluding that "the Court has inadvertently sent the lower courts stumbling into a no-man's land"); Bressman, How Mead Has Muddled Judicial Review of Agency Action, 58 Vand. L. Rev. 1443, 1475 (2005) ("Mead has muddled judicial review of agency action").

    126

    [15] JUSTICE BREYER attempts to clarify Mead by repeating its formulations that the Court has "sometimes found reasons" to give Chevron deference in a (still-unspecified) "variety of ways" or because of a (still-unspecified) "variety of indicators," ante, at 1004 (concurring opinion) (internal quotation marks and emphasis omitted). He also notes that deference is sometimes inappropriate for reasons unrelated to the agency's process. Surprising those who thought the Court's decision not to defer to the agency in General Dynamics Land Systems, Inc. v. Cline, 540 U. S. 581 (2004), depended on its conclusion that there was "no serious question . . . about purely textual ambiguity" in the statute, id., at 600, JUSTICE BREYER seemingly attributes that decision to a still-underdeveloped exception to Chevron deference—one for "unusually basic legal question[s]," ante, at 1004. The Court today (thankfully) does not follow this approach: It bases its decision on what it sees as statutory ambiguity, ante, at 996-997, without asking whether the classification of cable-modem service is an "unusually basic legal question."

    127

    [16] It is true that, even under the broad basis for deference that I propose (viz., any agency position that plainly has the approval of the agency head, see United States v. Mead Corp., 533 U. S. 218, 256-257 (2001) (SCALIA, J., dissenting)), some interpretive matters will be decided de novo, without deference to agency views. This would be a rare occurrence, however, at the Supreme Court level—at least with respect to matters of any significance to the agency. Seeking to achieve 100% agency control of ambiguous provisions through the complicated method the Court proposes is not worth the incremental benefit.

    128

    [17] The Court's unanimous holding in Neal v. United States, 516 U. S. 284 (1996), plainly rejected the notion that any form of deference could cause the Court to revisit a prior statutory-construction holding: "Once we have determined a statute's meaning, we adhere to our ruling under the doctrine of stare decisis, and we assess an agency's later interpretation of the statute against that settled law." Id., at 295. The Court attempts to reinterpret this plain language by dissecting the cases Neal cited, noting that they referred to previous determinations of "`a statute's clear meaning.'" Lechmere, Inc. v. NLRB, 502 U. S. 527, 537 (1992) (quoting Maislin Industries, U. S., Inc. v. Primary Steel, Inc., 497 U. S. 116, 131 (1990)). But those cases reveal that today's focus on the term "clear" is revisionist. The oldest case in the chain using that word, Maislin Industries, did not rely on a prior decision that held the statute to be clear, but on a run-of-the-mill statutory interpretation contained in a 1908 decision. Id., at 130-131. When Maislin Industries referred to the Court's prior determination of "a statute's clear meaning," it was referring to the fact that the prior decision had made the statute clear, and was not conducting a retrospective inquiry into whether the prior decision had declared the statute itself to be clear on its own terms.

    129

    [18] The Court contends that no reversal of judicial holdings is involved, because "a court's opinion as to the best reading of an ambiguous statute . . . is not authoritative," ante, at 983. That fails to appreciate the difference between a de novo construction of a statute and a decision whether to defer to an agency's position, which does not even "purport to give the statute a judicial interpretation." Mead, supra, at 248 (SCALIA, J., dissenting). Once a court has decided upon its de novo construction of the statute, there no longer is a "different construction" that is "consistent with the court's holding," ante, at 983, and available for adoption by the agency.

    130

    [19] Suggestive of the same chaotic undermining of all prior judicial decisions that do not explicitly renounce ambiguity is the Court's explanation of why agency departure from a prior judicial decision does not amount to overruling: "[T]he agency may, consistent with the court's holding, choose a different construction, since the agency remains the authoritative interpreter (within the limits of reason) of [ambiguous] statutes [it is charged with administering]." Ibid.

    131

    [20] Further deossification may already be on the way, as the Court has hinted that an agency construction unworthy of Chevron deference may be able to trump one of our statutory-construction holdings. In Edelman v. Lynchburg College, 535 U. S. 106, 114 (2002), the Court found "no need to resolve any question of deference" because the Equal Employment Opportunity Commission's rule was "the position we would adopt even if . . . we were interpreting the statute from scratch." It nevertheless refused to say whether the agency's position was "the only one permissible." Id., at 114, n. 8 (internal quotation marks omitted). JUSTICE O'CONNOR appropriately "doubt[ed] that it is possible to reserve" the question whether a regulation is entitled to Chevron deference "while simultaneously maintaining . . . that the agency is free to change its interpretation" in the future. 535 U. S., at 122 (opinion concurring in judgment). In response, the Court cryptically said only that "not all deference is deference under Chevron." Id., at 114, n. 8.

  • 7 Cass Sunstein, Cost Benefit Analysis and Arbitrariness Review

  • 8 Antonin Scalia, The Rule of Law as a Law of Rules

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