The primary architect of the Soviet Union's policies during the Cold War was Joseph Stalin. As General Secretary of the Communist Party from the 1920s until his death in 1953, Stalin shaped the USSR's domestic and foreign policies. His command during and after World War II established the Soviet Union as a superpower, leading to a post-war rivalry with the United States. His aggressive expansionist policies in Eastern Europe and the establishment of satellite states created the Iron Curtain, effectively dividing Europe. Stalin's regime, characterized by totalitarian control and purges, had a lasting impact on Soviet society and global politics during the Cold War era.