This article uses competing theories of civil-military relations to explain why the Soviet military failed to act in a decisive manner to prevent the collapse of the USSR in 1991. The norms and beliefs held by Soviet military officers—that is, the military's organizational culture—were crucial in shaping officers' behavior. The article tests this explanation against other approaches to civil-military relations and finds that the organizational culture framework is by far the most convincing. The article gives particular attention to the behavior of the Soviet armed forces during the attempted coup d'état in August 1991 and the events leading up to the dissolution of the Soviet state at the end of 1991.