Which leader was in charge of the Soviet Union during World War II?

Joseph Stalin was the leader of the Soviet Union during World War II, holding the position of General Secretary of the Communist Party and the head of government. His leadership was marked by a significant transformation of the Soviet Union into a major world power, especially in the context of the war. Stalin's policies of rapid industrialization and militarization contributed to the USSR's ability to withstand and eventually repel the Nazi invasion during Operation Barbarossa.

Moreover, under his command, the Soviet military played a crucial role in key battles such as the Battle of Stalingrad and the Siege of Leningrad, which were pivotal in shifting the momentum in favor of the Allies. Stalin's strategy and decisions during the war had long-lasting impacts on both the Soviet Union and the global balance of power after the conflict concluded. Understanding his role during this critical period is essential to comprehending the dynamics of World War II and post-war geopolitics.