Proportionality and Time

Proportionality in the resort to war determines a limit to the amount of harm it can be permissible to cause for the sake of achieving a just cause. It seems to follow that if a war has caused harm up to that limit but has not achieved the just cause, it should be terminated. I argue, however, that this is a mistake. Judgments of proportionality are entirely prospective and harms suffered or inflicted in the past should in general be ignored. Yet past losses that could be partially redeemed by the achievement of the just cause may be an exception.