Power, Alliance, and Major Wars, 1816-1975

For years, students of international politics have attempted to explain seemingly contradictory perspectives about the relationship between power distribution and the onset of war, and between alliance formation and the incidence of war. Power transition theorists claim that war is most likely when power is equally distributed among nations and that alliances have little or no impact on the likelihood of major wars, whereas balance-of-power theorists suggest that war is less likely when power is equally distributed and that alliances play a critical role in the incidence of war. In this research, several propositions suggested by the power transition theory are tested for major war cases from 1816 to 1975. The main findings show that alliances play a significant role in the incidence of major wars and that the probability of war increases when the two alliance coalitions, not the two nations in a dyad, have approximately equal power. These findings confirm neither the balance-of-power perspective nor the view of the power transition model. In addition, the power transition and the rate of growth hypotheses claimed by the power transition theory are not empirically supported.