The legal structure of warfare is a dramatic example of a changing regime, even while its fundamental principles remain constant. Conflict management asks that international actors devise and follow rules to prevent the reckless escalation and widening of conflicts—often requiring deterrence as well as defense—and to promote the termination of violence and the rebuilding of post-war confidence. Principles of humanity ask that conflicts be conducted in a way that minimizes the needless suffering of soldiers and protects noncombatant civilians. The application of these principles may not look the same in each era, with changes in technology, the character of conflicts, and the personality of the actors. Modern terrorism has salient differenc...