This article contends that the interaction between domestic circumstances in the USSR and the radical change in the international environment occasioned by the advent of the first Reagan administration played a substantial part in the early emergence of ‘New Political Thinking’ in the Soviet Union. That process had begun shortly after Brezhnev’s death. The Reagan factor loomed large in an internal Soviet debate over the direction of Soviet foreign policy. Four types of causal association are identified. While the Reagan administration was not the sole cause of the Soviet crisis that brought new thinking to the fore, it certainly contributed to a climate that strengthened the position of advocates of this perspective within the Soviet ruling elite.