Ideological Polarity and Balancing in Great Power Politics

AbstractThis article examines the international effects of a variable that has yet to be studied in a systematic manner in the international relations literature: the number of prominent, distinct ideological groups that are present in a particular system, which is a variable that I label "ideological polarity." My basic argument is that systems in which the great powers are divided into one, two, or three or more ideological groups (or "ideological unipolarity," "ideological bipolarity," or "ideological multipolarity," respectively) have very different dynamics, including major variations in overall threat perceptions among the great powers and the efficiency of the balancing process against perceived dangers. The effects of ideological polarity explain key outcomes that analyses based on power polarity cannot. I test the argument by examining great power relations in two cases: the decades after the Napoleonic Wars and the years leading up to the Second World War. Both periods were multipolar in terms of power but varied in terms of ideological polarity. The result was significant variations in states' core security policies for reasons consistent with the argument. ACKNOWLEDGMENTSFor detailed and insightful feedback on earlier versions of the article, I thank Steve Brooks, Tim Crawford, John Duffield, Henry Nau, Jennie Schulze, Jeff Taliaferro, Tryg Throntveit, Will Walldorf, Patricia Weitsman, Bill Wohlforth, and the seminar participants at Dartmouth University's Dickey Center for International Understanding and Cornell University's Judith Reppy Institute for Peace and Conflict Studies, as well as the editors and three anonymous reviewers at Security Studies.