Chalmers Johnson (2004)

The danger I foresee is that the United States is embarked on a path not unlike that of the former Soviet Union during the 1980s. The USSR collapsed for three basic reasons — internal economic contradictions driven by ideological rigidity, imperial overstretch, and an inability to reform. Because the United States is far wealthier, it may take longer for similar afflictions to do their work. But the similarities are obvious and it is nowhere written that the United States, in its guise as an empire dominating the world, must go on forever.