Henry Wallace
Can you imagine if he had become president after FDR died? There would be no Cold War, which would make all the liberals, Dixiecrats and conservative Republicans very angry, lol.
Also no Korean War or Vietnam War, etc... Germany would probably have reunified in 1950 just like Austria, a neutral country. The space race would have been an unified thing with the Soviets. And early desegregation, and free universal health care.
Some weirdos think that Foro Sao Paulo is a secret society of evil commies, like the Injustice League or something comical like that. lol.