A Challenge to the Reigning Theory of the Just War

Troubled times often gives rise to great art that reflects those troubles. So too with political theory. The greatest work of twentieth century political theory, John Rawls's A theory of justice, was inspired in various respects by extreme social and economic inequality, racialized slavery and racial segregation in the United States. Arguably the most influential work of political theory since Rawls—Michael Walzer's Just and unjust wars—a sustained and historically informed reflection on the morality of interstate armed conflict—was written in the midst of the Vietnam War. It should be no surprise, then, that the bellicose period of the past 20 years should give rise to a robust new literature in political theory on the morality of armed conflict. It has been of uneven quality, and to some extent episodic, responding to particular challenges—the increased prevalence of asymmetric warfare and the permissibility of preventive or preemptive war—that have arisen as a result of specific events. In the past decade, however, a group of philosophers has begun to pose more fundamental questions about the reigning theory of the morality of armed conflict warfare—just war theory—as formulated by Walzer and others. Jeff McMahan's concise, inventive and tightly argued work Killing in war is without doubt the most important of these challenges to the reigning theory of the just war. This review article discusses McMahan's work, some of the critical attention it has received, and its potential implications for practice.