Just-War thinking today
Learning and applying the principles of a rich Catholic tradition
This section presents 26 short essays on just-war thinking (also offered in audio recordings), intended both to inform readers and to stimulate discussion on a topic that lends itself to lively debates.
The series begins with a summary of the basic principles of the just-war tradition, tracing its development from St. Augustine through St. Thomas Aquinas and the Jesuit scholastics to some neglected 20th-century moralists and strategists. The last several offerings cover issues of nuclear strategy and the new moral issues surrounding the use of artificial intelligence and unmanned warfare.
[For a fuller explanation of what this series is about, see my original invitation to participate: the first short essay in this series.]
Although we often hear talk about “just-war theory,” the tradition is not merely an abstract theory; the just-war tradition has developed and refined a set of principles by which we can appraise the morality of a conflict. Moreover, these principles do not simply test whether a war is justified— whether there is a just cause for the conflict— but also whether the was is conducted justly. A just cause does not excuse military actions that are themselves unjust.
The application of these moral principles, however, involves prudential decisions, on which reasonable people may, and frequently do, disagree. Thus the topic is ripe for debate. My hope is that this series will help to stimulate and guide such debates.
My original outline for this series was based on my lesson plan for a seminar offered to college upperclassmen. In a bid to stimulate more debate among readers, I changed by plan, so that the series does not follow the outline that I originally presented. Nevertheless I would encourage readers to begin with the earliest posts, to become acquainted with the framework of just-war principles, before moving on to read later installments.
This series of essays has now concluded, but I hope that the discussion can continue. And since my goal is to encourage open debate, I invite all readers to contribute their thoughts, with the confidence that I— and, I hope, other readers— will respond. Please do add your comments, and join in the debate!




Well, with the Deputy Chairman of the Russian Federation’s Security Council warning about the consequences if UK and France give Ukraine a nuclear weapon our principles may soon be melted rather than applied. Not since the Cuban Missile Crisis has humanity been so close to self-annihilation. Does anyone seem to care, apart from us few tinfoil hatters?