Polarity, the Offense-Defense Balance, and War

Bipolar systems are inherently more stable than multipolar configurations of power, Kenneth Waltz argues. His empirical justification for this conclusion relies on the multipolar systems that preceded the two world wars and the bipolar Cold War. The weakness of Waltz's argument is the small number of cases and the failure to consider alternative explanations for different levels of war in the three periods. In another historical period of both multi- and bipolarity—Europe from 1495 to 1559—I have found that polarity cannot account for the constant level of instability across a change in polarity in the system. Instead, the offense-defense balance, which includes the technical military balance, the cumulativity of power resources, and strategic beliefs, explains instability in the period. Drawing on this alternative theory, I reassess the high level of stability associated with the Cold War and speculate on the level of stability we can expect in the post-Cold War period.