America only works because of its symbolism- back in its day, it was "the promised land" , the place where you could go and start anew, and live happily ever after (as an idea), so people flocked to it like mad.
Obviously it turned out to be bull, but nevertheless, America maintained its propaganda after that.
I think(america also thinks) that its moment of glory was WW2. Smelling opportunity, America baited Japan into bombing a useless abandoned harbour, now way too famous, and then had an excuse to go bomb their way into war for profit and glory, seeing as how almost none of the war took place on their homeland (sounds very familiar, amiritie?)
Anyway, after that America never shut up about their awesome victory, they slowly but surely installed themselves in most non-communist country and sealed their image as Jesus-incarnate.
Granted, America did put itself on its feet pretty well, and it worked fine on its own, but it didn't actually give a damn about other countries that worshipped it.
Like a popular jock, it smiled a perfect smile and walked down the alley with 2 cheerleaders in its arms, and spit on the notebook of the geek who asked for its autograph.
In short, America is good for its image , not its content, under that image it's still a heartless bastard like most "saviour" countries out there, it's just very good at putting on a convincing show for ya.