Introduction to the Morality of Defensive War

Conventional just war theory—grounded in the founders of public international law and most prominently defended in the modern era by Michael Walzer—has three central tenets. First, unprovoked military aggression against a political community justifies the recourse to lethal force. Second, combatants on either side of a conflict are under an equally strict duty not to intentionally kill noncombatants. And third, combatants are equally liable to be killed, regardless of whether their side went to war justifiably. In recent years, these principles of national defence, noncombatant immunity, and the moral equality of combatants have come under profound scrutiny from a revisionist group of just war theorists, who have applied the tools of contemporary analytical moral and political philosophy to the morality of war, and found the existing arguments for these conventional positions wanting. The success of the revisionists’ critical work, however, has not been matched by their delivery of positive alternatives to the conventional orthodoxy. This is particularly noticeable with respect to the morality of defensive wars, which their individualist, self-defence based model of war seems particularly ill-equipped to explain. This introduction sets out the main debates and problems addressed in the book, and outlines its three part structure.