Grasping the Technological Peace: The Offense-Defense Balance and International Security

Offense-defense theory argues that international conict and war are more likely when offensive military operations have the advantage over defensive operations, whereas cooperation and peace are more likely when defense has the advantage. According to the theory, the relative ease of attack and defense—the offensedefense balance—is determined primarily by the prevailing state of technology at any given time. When technological change shifts the balance toward offense, attackers are more likely to win quick and decisive victories. This prospect of quick and decisive warfare exacerbates the security dilemma among states, intensiŽes arms races, and makes wars of expansion, prevention, and preemption more likely. When technological innovation strengthens the defense relative to the offense, states are more likely to feel secure and act benignly.1 Offense-defense theory has deep roots, but has become increasingly popular in international relations scholarship and foreign policy analysis in recent years. The idea that the nature of technology affects the prospects for war and