The USSR would span its territories in the 80s but be led by a competent Marxist leninist party. Same for the Warsaw pact countries and Yugoslavia. These were caused by revolutions popping up all across the globe and other areas.
The US choice would have itself devolve into chaos while its power and influence decreases. Infighting would break the US into pieces but territories like hawaii and alaska would gain independence. The main government would be torn asunder and the CIA rogue and unfunded.
Damn, that would be a gigantic global movement, it would essentially push most anti-imperialist countries to a crossroads of capitalism or socialism rather than a state capitalist anti-imperialism. Like Nicaragua and Venezuela and Palestine could become Marxists in that case that would be so much more based than the fall of the current global leader. Whoever Western Europe supports after the USA falls will continue the military, but a giant global alliance against capitalism would fight against that