This essay seeks to offer a new structural account of the outbreak of World War Il and a more determinate balance-of-power theo based on two modifications of Kenneth Waltz's theory of international politics. First, the distribution of power in the international system is more precisely specified. Instead of simply counting the number of Great Powers to determine system polarity, limits are divided into poles and middle powers and weighted according to their relative power capabilities. Second, states are coded as either status quo or revisionist. The revised theory more accurately reflects the twin foci of classical realist thought: the power and interests of states. Several deductions from the model, however, contradict basic tenets of balance-of-power theory. At the theoretical and empirical levels, the theory is used to examine the dynamics of tripolar systems and to explain the alliance strategies of the seven major powers (three of which were poles) shortly before and during the Second World War.
