Janina Dill, “Applying the Principle of Proportionality in Combat Operations” (2010)
Making Proportionality Work

Applying proportionality starting with necessity. The first step in rendering the principle of proportionality more effective is understanding the fact that necessity is a precondition of its fulfilment. Necessity sets a lower bound for proportionality. Damage to civilians that is not necessary is never proportionate. Some militaries already go to great length to minimize the expected collateral damage from a chosen target. Practitioners relate that once the collateral damage expected from an attack can be no further minimized, for instance through the choice of a different weapon or a change in the angle or time of attack, the proportionality principle is considered fulfilled and a “go” for the planned attack is likely. This is a necessity judgment, but an incomplete one. Meeting the requirement of necessity also means searching for alternative targets. Militaries do not yet routinely establish several courses of action to implement the commander’s intent and then pick the one with the best proportionality calculus.

One could argue that what is necessary is just as much subject to interpretation as is what is proportionate. However there is an important difference between the two criteria. While proportionality does not imply an absolute standard, necessity, at least, in theory does. For an attack to have been necessary there can have been no alternative course of action with a reasonable chance of achieving a certain military advantage that would have caused fewer civilian casualties. The epistemic conditions under which a combatant could establish this with certainty will never be present in combat. However the theoretical scenario, in which the condition of necessity is met, provides the basis for establishing concrete criteria for its application in practice. To the contrary, as long as notions of excess are an essentially private and subjective matter, the absence of the intent not to excessively harm civilians cannot even in theory be rendered manifest. However, the protective capacity of proportionality exceeds that of necessity. Incidental harm might be necessary but still disproportionate. In the interest of protecting civilians from harm should we not therefore abstain from emphasizing necessity in the application of proportionality? In light of the striking inadequacy of existing attempts to apply proportionality, the clarity afforded by necessity is invaluable. We can never answer the question “how much is too much?” but by starting with necessity the law can better guide and arbitrate, and thereby also better protect the civilian population. However, it is important that in the means to ends judgment necessity does not simply replace proportionality but offers a place to start and a complement to unguided discussions about excess. It needs to be stressed that achieving this condition is still not enough for an actor wanting to do the right thing in combat, because, as mentioned, something might be necessary yet still disproportionate.

Applying proportionality by drawing on procedural requirements. The endeavour to make the principle of proportionality more effective involves a second step. Article 57 of the First Additional Protocol obliges belligerents to “take all feasible precautions” and constant care with a view to implementing proportionality and distinction. It contains three concrete obligations – to refrain from launching a potentially disproportionate attack, to cancel or suspend a potentially disproportionate attack as well as to always choose the target with the most favourable anticipated proportionality calculus. All three obligations are already implicit in the principle of proportionality and therefore receive relatively little attention during combat operations. But the added value of Article 57 lies in the fact that it prescribes actions for those who intend not to harm civilians excessively. It thus bears the potential to more concretely connect intention and outcomes in the conduct of hostilities. The ICTY has indeed drawn on Article 57 in allegations of disproportionate attack. However Article 57 is itself rather indeterminate, raising the question of what it means to do “everything feasible”. In order to realize the potential of procedural requirements to render proportionality more effective the obligation contained in the provision should be operationalized in a transparent and systematic manner, preferably by an international body that commands authority in matters of law and war.