The War Years
The security that Stalin bought with the German treaty was short-lived. Hitler repudiated the agreement in 1941, and Russian, Belorussian, and Ukrainian territory subsequently became the scene of fierce fighting and the eventual repulsion of a huge Nazi invasion force. Stalin was able to rally patriotic support for the war effort, and Soviet forces entered Berlin triumphantly in April 1945. Together with the United States, the Soviet Union entered the postwar era as a superpower.