have been overrun nearly so easily if not for Stalin agreeing to a non-aggression pact with Hitler and then dividing Poland between them. That pact allowed Hitler to turn westward to conquer Europe without having to worry about his eastern flank. But yes, once Hitler invaded the Soviet Union, Stalin got in the game. But even then the Soviets needed massive amounts of aid, materials, supplies, etc. from the U.K. and then the U.S. In the end, the Soviets lost far more people than any other ally. Far more. Perhaps they never should have helped Hitler kick the whole thing off.