Who was the leader of the Soviet Union during World War II?

The leader of the Soviet Union during World War II was Joseph Stalin. He rose to power in the 1920s after the death of Vladimir Lenin and became the General Secretary of the Communist Party. Under Stalin's leadership, the Soviet Union was involved in significant events during the war, including the defense against the German invasion in 1941 and major battles such as Stalingrad, which marked a turning point in the war in favor of the Allies. Stalin's policies, including extensive industrialization and collectivization, dramatically affected the Soviet Union's military capabilities and its role in the broader conflict. This period also saw Stalin's leadership characterized by a repressive regime, significant purges, and the establishment of a powerful state apparatus that contributed both to the Soviet war effort and to internal strife.