No single nation, or group of nations, succeeds in ganging up against the U.S. to supplant its global hegemony. Europe remains an unwieldy collection of states, China becomes consumed with regional differences and secessionists, and India remains burdened by poverty. The United Nations, meanwhile, remains ineffective, dooming predictions of world government. The U.S. avoids a world war, and its military entanglements are increasingly narrow and contained. Rather than impose its views on the world, the U.S. seeks more cooperative ways of settling differences, relying increasingly on civil society and multinational corporations to spread the American message beyond U.S. borders.
Rigidity is what killed a lot of empires.
By 2500, U.S. power rests largely on shared values among its citizens, notably a faith in openness, which enables the U.S. to adopt the best qualities from around the world as its own and in turn to spread these qualities everywhere else. In the process, the whole global middle class is Americanized, speaking English and consuming roughly the same media, goods and services. Technical innovation, meanwhile, mutes business cycles so that the world economy avoids a depression, facing only regional crises. Income disparities grow larger, however, with growth rates in the richest countries continuing to outpace those of the poorest. Growth disparities ensure a steady flow of talented people into the rich world, especially the U.S., further enhancing its intellectual hegemony.