World War II left Eurasia in ruins, and two huge continental superpowers, the USA and the USSR, dominating the world. Of the two, the USA had by far the bigger economy and superior military force. The wartime alliance of the two powers did not last long: Within two years, they had begun a bitter global conflict, the Cold War. Because both sides had nuclear weapons, this war threatened to exterminate humanity itself. Fortunately, the conflict quickly stabilized in Europe, dividing it into two spheres of influence, and both powers stepped back from nuclear confrontation over Cuba. But in the rest of the world, local upheavals threatened to draw in the superpowers, making each civil war and rebellion in the Third World a test of the superpowers’ “credibility.”
The two most destructive wars took place in Korea and Vietnam. In neither one did either superpower gain total victory. Korea remains a divided nation, and in Vietnam revolutionary nationalists successfully expelled French colonialists, their Vietnamese collaborators, and their American supporters. The Soviet Union, emboldened by American defeat, moved into Afghanistan, but faced its own Vietnam there. By 1980, the superpowers no longer seemed to dominate the world.
Despite the superpower confrontation, the postwar world economy grew at an unprecedented rate for thirty years.