Offense, Defense, and the Causes of War

Stephen Van Evera of the Massachusetts Institute of Technology argues that the likelihood of war increases when conquest is easy, and that changes in the offense-defense balance can greatly heighten or lessen the chances of war. Van Evera suggests ten “war-causing effects” that emerge when offense is dominant. He tests his claims with the help of three case studies—Europe since 1789, ancient China, and the United States since 1789. Van Evera concludes that “offense-defense theory has the attributes of a good theory.” Not only does it have “wide explanatory range,” but it also has “wide real-world applicability.”