The discourses surrounding the development of the just war tradition and the discourse surrounding the development of international criminal law have long influenced one another.1 Walzer reminds us that Grotius and Pufendorf deliberately incorporated just war theory into International law.2 Still, the international criminal law and just war discourses are conceptually and practically very distinct, and few participants in either discourse directly utilize the terms of the other.3 In what follows, I argue that each discourse needs the other. Recent rapid developments in the field of international criminal law have the potential to remake the just war tradition by institutionalizing criminal accountability for the most egregious violators of just war norms. That is only possible, however, to the extent that international criminal law tends to codify norms that reflect the moral principles of the just war tradition.