CONCENTRATION, POLARITY, AND THE DISTRIBUTION OF POWER

Scholars of international relations generally rely on polarity to meas ure the distribution of power. I argue that another feature of this di stribution-concentration-should be considered more carefully in analys es of international relations. Much of the recent literature on the di stribution of power draws on analogies between the structure of market s and the structure of the international system. Concentration is more consistent than polarity with the microeconomic foundations of these studies. Further, using polarity to measure the distribution of power also requires analysts to assume (often implicitly) that: (1) inequali ties among major powers are unimportant features of the global distrib ution of power; and (2) nonpolar major powers should be ignored in str uctural analyses of international relations. I maintain that these ass umptions are at odds with many leading explanations of international r elations. A number of prominent theories of balancing behavior, the on set of war, and the international political economy emphasize both the importance of both major (as well as polar) powers and the inequaliti es in power among them. As a result, analyses that center solely on th e effects of polarity are likely to offer incomplete explanations of b alancing behavior, the onset of war, and the international political e conomy. Since concentration measures both the number of major powers a nd the inequalities in power among them, these analyses may be enhance d substantially by considering the influence of concentration, as well as polarity.