An Evolutionary Approach to the Study of Interstate

Recent research on interstate conflict and rivalry has shown that most conflict occurs between long-time rival countries, and has used enduring rivalries to test propositions on arms races, deterrence, and power transitions. Yet most of this research has focused on the dynamics of already-established rivalry; little is known about how adversaries become long-term rivals. The present effort attempts to account for the origins of rivalry with an evolutionary model of interstate rivalry that treats rivalry as a dynamic process, evolving out of interactions between two adversaries. Empirical analyses reveal that the context of recent relations between two adversaries has a great influence on their conflict behavior, particularly on their probability of engaging in further conflict along the path toward or away from enduring rivalry. As two adversaries accumulate a longer history of conflict, their rivalry relationship tends to become "locked in" or entrenched, with future conflict becoming increasingly difficult to avoid; specific characteristics of their past confrontations can hasten or reverse this movement toward rivalry. This paper concludes by discussing the implications of this evolutionary model for the understanding of rivalry, conflict, and world politics more generally.