This essay explores the idea of just war in two ways. Part I outlines the formation, early development, and substantive content of just war tradition in its classic form, sketches the subsequent development of this idea in the modern period, and examines three benchmarks in the recovery of just war thinking in American thought over the last four decades. Part II identifies and critiques several prominent themes in contemporary just war discourse, testing them against the context, purpose, and content of the just war idea in its classic form. My argument throughout is that the historical substance of just war tradition needs to be respected in contemporary just war discourse, both to discipline that discourse and to engage contemporary moral reflection with the values embodied in just war tradition.