This article explores the influence of cognitive and institutional factors in shaping state behavior. In particular, the author examines their role in the Gorbachev foreign policy revolution, developing an analytic framework that integrates domestic and international sources of state behavior. While it is dear that a new ideology of international affairs—one developed and conveyed by Soviet specialists—played a critical role in shaping Gorbachev's “new thinking,” its ability to influence policy was at different times constrained or magnified by institutional and political variables. Moreover, the relevance of this new ideology to policy debates, particularly during the early years of the Gorbachev era, depended crucially upon the efforts of individual “policy entrepreneurs” and open policy windows. How wide these windows opened was, in turn, partly a function of the USSR's international environment.