Proportionality and Distinction When Collateral Damage Is a Certainty

Over at Opinio Juris, Kevin Jon Heller responds to my earlier post regarding the BIJ report on drone strikes in Pakistan, and in doing so draws attention to a very interesting question.  [Update: see Dapo Akande's follow-up post here] [Background: BIJ's report asserted that in the aftermath of drone strikes, follow-on strikes have been conducted during rescue operations and funerals.  BIJ also offered legal commentary that I read as suggesting that such strikes violated the principle of distinction.  I responded by arguing that the strikes certainly raised issuses under the principle of proportionality, but--assuming that the strikes were targeting fighters and only incidentally harming non-fighters--that they did not also raise a distinction issue (other than, of course, the ongoing debate as to whether it is proper to target fighters who are not currently directly participating in hostitilies but who do have a continuous combat function within an organized armed group that is party to the conflict).] Kevin's question: Are such "follow-on" strikes in violation of the principle (articulated in AP I art. 50(3)) to the effect that the presence of non-civilians amidst the civilian population does not deprive that populatioon of its civilian character?   Kevin declares the existence of the non-deprivation rule to be black letter IHL, and I certainly agree.  But is the rule necessarily violated in the follow-on strike scenario?  I am doubtful. First, I think we can all agree that the follow-on strike scenario is not what we might call a core violation of the non-deprivation rule.  That is, I don't think anyone is suggesting that the US government is taking the position that the presence of fighters amidst civilians at funerals or at rescue sites has the effect of depriving the civilians of their otherwise-protected character, making them directly targetable in their own right even though not directly participating in hostilities.  There is no green light to bomb funerals and post-blast rescue operations without regard to the civilian status of some persons present on site; one must consider proportionality. The more interesting question is whether the non-deprivation rule extends to the distinct scenario in which the pre-strike collateral damage assessment suggests a near certainty that some number of civilians will in fact be killed (given bomb blast radius, proximity to the legitimate target, etc.).  Put another way, can you say that an attack is indiscriminate, or more strongly still that the attacker is purposefully targeting civilians, where the attacker knows or should know that using a particular means to kill a targeted fighter will also result in the death of some number of civilians?  Bear in mind that this scenario unquestionably raises a proportionality concern. But does it also raise a distinction concern?  I do not think so (though--pace the trial court judgment in Galic--I do appreciate that such circumstances can raise evidentiary questions about what the attackers true intentions were).