ABSTRACT
The ad bellum criteria of just war theory are to state individually necessary and jointly sufficient conditions for the justifiability of resorting to or continuing a war. The chapter will argue that legitimate authority is not a necessary condition. It further shows that just cause is not independent of proportionality, nor can it be understood as an aim or as (necessarily arising from) a rights violation. Rather, just cause is a specific state of affairs, and it has to exist continuously throughout the war for the war to be justified. Separate criteria for when to stop a war are not needed. The right intention requirement will be interpreted as a knowledge requirement that constrains the interpretation of other criteria and militates against the “fact-relative justification” favored by “revisionists.” Without it, just war theory would be impractically demanding. Prospects of success and last resort will turn out to be neither independent nor necessary criteria of jus ad bellum but merely considerations to be taken into account in proportionality assessments. The chapter concludes that agents satisfy jus ad bellum if they know (which does not require certainty) that they have a just cause and that their resort to war will indeed be proportionate.
