Just and Unjust Wars

Overview

Just and Unjust Wars, published in 1977 by Michael Walzer, is the most influential work of just war theory of the twentieth century. Walzer's aim is to recover the moral language of war — to show that war is not merely a realm of necessity and violence but a human activity that is subject to moral judgment. The book draws on the Western just war tradition, from Augustine and Aquinas through Grotius and the modern laws of war, and it uses historical case studies to test and refine the moral principles that govern the conduct of war.

Walzer argues that the moral reality of war is structured by two sets of principles: the principles of jus ad bellum, which govern the decision to go to war, and the principles of jus in bello, which govern the conduct of war once it has begun. The central principle of jus ad bellum is that aggression is a crime: the unprovoked attack by one state on another is the supreme international crime, and it justifies a defensive war. The central principle of jus in bello is the principle of noncombatant immunity: soldiers may be targeted because they are engaged in the business of war, but civilians may not be intentionally attacked.

Key Ideas

Walzer's most important contribution is his argument for the "moral equality of soldiers" — the idea that soldiers on both sides of a war, the aggressor and the defender, are equally subject to the same rules of conduct. The soldier who fights for an unjust cause is not a criminal; they are a soldier, and they are entitled to the same protections and subject to the same prohibitions as the soldier who fights for a just cause. This principle is the foundation of the laws of war, and it distinguishes the just war tradition from the pacifist tradition, which condemns all war, and from the realist tradition, which denies that war is subject to moral judgment.

Influence

Just and Unjust Wars has been enormously influential in the academic study of the ethics of war, in the development of international law, and in public debate about the morality of war. It has been the subject of extensive criticism, particularly from those who argue that Walzer's account of noncombatant immunity is too permissive, and from those who argue that the just war tradition is itself a form of ideology that legitimates war.

Sources

1. Stanford Encyclopedia of Philosophy, "Michael Walzer." Comprehensive survey of Walzer's life and thought.
2. Stanford Encyclopedia of Philosophy, "Just War Theory." Analysis of the just war tradition.