Even in just wars we infringe the rights of countless civilians whose ruination enables us to protect our own rights. These civilians are owed compensation, even in cases where the collateral harms they suffer satisfy the proportionality constraint. I argue that those who authorize or commit the infringements and who also benefit from those harms will bear that compensatory duty, even if the unjust aggressor cannot or will not discharge that duty. I argue further that if we suspect antecedently that (...) we will culpably refrain from compensating those victims post bellum, then this makes satisfying the war’s proportionality constraint substantially more difficult at the outset of the war. The lesson here is that failing to take duties of compensation in war seriously constrains our moral permission to protect ourselves. (shrink)