Power Parity, Commitment to Change, and War

Starr (1978) argues that the initiation of war requires both opportunity and willingness. Most theories of international conflict, however, consider only one of these conditions. Power transition theory, which focuses on power parity as opportunity and negative evaluations of the status quo as willingness, is an exception. Although the logic of the theory is compelling and empirical support impressive, the theory suffers from a lack of generalizability, and from inadequate conceptualization and operationalization of evaluations of the status quo. We offer preliminary corrections for both of these weaknesses by (1) depicting the international system as a series of hierarchies rather than as a single hierarchy, thus providing some generalizability; and (2) using extraordinary military buildups to evaluate the relative commitment of the challenger and the dominant power to the modification or maintenance of the status quo, respectively. We argue that the probability of wars between contenders in local or international hierarchies increases significantly when power parity is achieved, presenting the potential challenger with the opportunity to successfully challenge the dominant state, and when the challenger's extraordinary buildup exceeds that of the dominant power, revealing its willingness and commitment to change. Empirical evaluation of the conflict behavior of major power contenders and of a subset of minor power contenders provides strong support for our reconceptualization of power transition theory.