ABSTRACT
Walzer’s conception of just cause is among those threads of the tradition sometimes referred to as the aggressor/defender paradigm. In Walzer’s formulation, offensive war (war for any purpose other than defense) is always wrong. Defensive wars are assumed to be justified, except the defensive wars of societies engaged in massive human rights violations (genocide, enslavement, and widespread massacre).1 One element of Walzer’s view is the idea that “no war, as medieval theologians explained, can be just on both sides.”2 In Walzer’s understanding, all offensive war, or any armed attack on the political independence or territorial integrity of a sovereign state is a crime of aggression. “Nothing but aggression can justify war,” Walzer writes. “Nothing else warrants the use of force in international society.”3
