We lived for a greater part of the post-war period in the Cold War. The Cold War placed a premium on loyalty to alliances, and it tended to freeze a certain power situation. That contributed to the special position the United States and the Soviet Union, as it was then, occupied. Of course that whole world, that framework, disappeared 20 years ago. Part of the diffusion of power is the consequence of the disappearance of the Cold War.
Power is undoubtedly shifting in the world in the ways Peter Harder has described, but I would think for all that, when we get past the present turmoil--as we all hope to--it will still appear that the United States is the most powerful country in the world. And whether it's relatively less powerful five years from now than it was five years in the past, nothing is going to change the fact that we will still be living next door to it.