Abstract
The individualist nature of much contemporary just war theory means that we often discuss cases with single attackers. But even if war is best understood in this individualist way, in war combatants often have to make decisions about how to distribute harms among a plurality of aggressors: they must decide whom and how many to harm, and how much to harm them. In this paper, I look at simultaneous multiple aggressor cases in which more than one distribution of harm among aggressors is available. I show how such cases pose deep questions concerning the nature, role, and scope of the necessity principle, and its relationship to both liability and narrow proportionality. I argue that a hitherto unrecognised measure – ‘narrow proportionality shortfall’ – and its distribution is relevant in choosing how to distribute harms across aggressors. I then extend this analysis to show how this may help us with a puzzle concerning sequential attacks.