Actually, the U.S. has been behaving the way it has in the past ten years out of deference to the opinions of rest of the world. Were the U.S. to start acting as though it had nothing to prove to anyone, we wouldn't be in the position we're in now. Our current problems are a result of attempting to please all of the critics that have accumulated since we acquired superpower status in the first place.
Don't get me wrong. I don't think we should have listened to Europe whine about us, or the Middle East whine about us, or communists of every stripe from Russia to Asia to Africa to South America whine about us. To this day, the accusations levelled against us have been bull****, twisted by the envy and resentment of liars and idiots to make us out to be some kind of bully. When we are asked for help, we're accused of policing the world. When we don't help, we're accused of greed. We have tried to answer both sides of that for decades and what you see now is the end result.
So you know what? **** off. We haven't tried to conquer a goddamned thing and the rest of the world needs to stop blaming the boogeyman in the western hemisphere for their failures as nations and cultures. Even in the condition we're in now, we're still more awesome than you. It'll take more than half a century of socialism creeping through our schools and banks, or primitive, tribalist zealots throwing temper tantrums to make a third world country out of America.