Power Differentials and War in Rival Dyads

The relationship between static and dynamic power distributions and war is a central element in the realist literature of international politics. The distribution of power and shifts in these distributions are held to be a principal source of conflict in works from Thucydides to Waltz. Most attempts to test empirically for a structural association between capability distributions and conflict have treated disputes as independent events; however, over the last two centuries a disproportionate amount of interstate conflict has occurred in the context of extended dyadic rivalries. This study focuses on the conflict patterns of these “enduring rivals.” Based on a Markov chain analysis of 456 militarized disputes occurring between 1816 and 1986, the findings indicate that power parity and shifts toward parity are approximately twice as likely to be associated with war as is a condition of power preponderance. By definition, rival dyads have issues in conflict. Equality of power or shifts toward equality create a situation in which both sides can perceive the potential for successful use of force. The findings generated in this analysis indicate that with such power distributions war between rival nations is most probable.