What does it mean to say that international humanitarian law (IHL) “accounts for” military necessity? According to one theory, unqualified IHL rules exclude not only military necessity pleas but also humanity pleas in support of deviant behavior. Three propositions underpin this view. They are, first, that military necessity generates imperatives; second, that the imperatives emanating from military necessity inevitably conflict with those emanating from humanity; and third, that all positive IHL rules embody the military necessity-humanity interplay in the process of their norm-creation. In lieu of what may be termed an “inevitable conflict” thesis, this Article proposes and develops a “joint satisfaction” thesis. In the process of IHL norm-creation, military necessity does not furnish the law with reason to obligate or forbid given conduct. Rather, it only generates permissions. It not only robustly permits pursuing military necessities and avoiding non-necessities; it also permits, albeit moderately, forgoing success and inviting failure. In other words, military necessity is normatively indifferent. By acting as non-indifferently exhorted or demanded by humanity, the belligerent never acts in a manner affirmatively contrary to what military necessity indifferently permits. Where both humanitarian exhortations or demands and military necessity’s indifferent permissions are at stake, one always jointly satisfies them by acting in accordance with the former. When the framers of IHL validly posit an unqualified rule regarding given conduct, the rule does two things. First, it unqualifiedly obligates the pursuit of joint military necessity-humanity satisfaction with respect to the conduct in question. Second, this rule extinguishes any indifferent permission, including that emanating from military necessity, not to pursue the said satisfaction. It is for this reason, rather than the empirically troublesome claim that every positive IHL rule embodies the military necessity-humanity interplay, that unqualified IHL rules admit no military necessity and other de novo indifference pleas. The same does not necessarily hold for non-indifference considerations. It is possible that these latter considerations may survive the process of IHL norm-creation. The mere fact of an IHL rule being validly posited may not resolve the relatively rare, yet genuine, norm conflict that arises where the said rule unqualifiedly obligates certain action while humanity exhorts or demands contrary action.
Hayashi, Nobuo (2013) Military Necessity as Normative Indifference, Georgetown Journal of International Law 44 (2): 675–782.