The Ethics of War: A Modern Perspective

Mental models to analyze wars of the present and the past

The ethical evaluation of war has often been framed by the Just War Tradition, a set of criteria developed to assess whether engaging in war is morally justifiable and how war should be conducted. This tradition, rooted in both Western and Eastern philosophies, establishes two key principles: jus ad bellum (the right to go to war) and jus in bello (the right conduct in war).

Jus ad Bellum insists that a war must have a just cause—such as self-defense or protecting others from significant harm—and must be waged by a legitimate authority. War must also be a last resort, with all non-violent options exhausted, and there must be a reasonable chance of success. Moreover, the anticipated benefits of war must outweigh the expected harm.

Jus in Bello dictates that combatants must distinguish between combatants and non-combatants, ensuring civilians are not intentionally targeted. The use of force must be proportional to the military objective, and unnecessary suffering must be avoided.