Contemporary just war theory is divided into two broad camps: revisionists and traditionalists. Traditionalists seek to provide moral foundations for something close to current international law, and in particular the laws of armed conflict. Although they propose improvements, they do so cautiously. Revisionists argue that international law is at best a pragmatic fiction—it lacks deeper moral foundations. In this article, I present the contemporary history of analytical just war theory, from the origins of contemporary traditionalist just war theory in Michael Walzer's work to the revisionist critique of Walzer and the subsequent revival of traditionalism. I discuss central questions of methodology, as well as consider the morality of resorting to war and the morality of conduct in war. I show that although the revisionists exposed philosophical shortcomings in Walzer's arguments, their radical conclusions should prompt us not to reject the broad contemporary consensus, but instead to seek better arguments to underpin it.