well the main factors will be less and less control of the worlds oil, the breakdown of the vital petro-dollar cycle due to the rise of the euro, more and more countries will trade their oil in euros instead of dollar due to the ever increasing eu market economy (already larger than the u.s's). huge expenditure on wars (there will be plenty more to come, the next few are pretty obvious) in an attempt to control natural resources (all the west vs islam bullshit is just a cover of the real issues of course). Alliances will become harder and harder to make as world public opinion is already hugely anti-american (please bear in mind its the government that everyone hates, not the people). the empire will crumble, but as someone already said, like all before (rome, china, spain, france, britain etc.), the original country will survive, and still be quite wealthy. note to all americans: dont be disheartened, most european countries had vast empires once, but these days we are doing fine as equals, and have worked with each other instead of against each other to make life better for all our citizens. so its gonna be fine. China, however, scares the fuck out of me though...