Abstract

This paper discusses the novel versions of the right intention and proportionality conditions in the ius ad bellum proposed in Chapter 3 of Frances Kamm’s Ethics for Enemies. It argues that Kamm is right to weaken the right intention condition to require, not positively intending a war’s just cause, but only having that cause’s presence be a necessary condition for war, but wrong to place no limits on why one makes a just cause necessary. It then argues that the weakening she proposes of Jeff McMahan’s very strict interpretation of proportionality does not go far enough. She argues that “conditional just aims” such as disarming an aggressor and deterring future aggression can count toward a war’s proportionality only if they will follow from harms needed to achieve the war’s initial just cause but not if they require additional harms. The paper argues that such aims can justify additional harms.