The Power Transition Theory is a geopolitical model that explains the pattern of war and peace between nations. According to this theory, war is most likely to occur during a transition of power from one dominant state to another. The theory was first proposed by A.F.K. Organski in 1958, and has since been developed and refined by subsequent scholars.
Source: Organski, A. F. K. (1958). The Stages of Political Development. World Politics, 10(2), 166-192.