Prism

Although our response wouldn't be to nuke them, if you know anything about international politic's there are plenty of ways of avoiding paying up when called to do so.

China can overtake the US in two ways: become the largest economy (which it is projected to become) or have the US fall. China would not overtake the US by calling on its debt, especially given how if it wanted to get ahead it could (and probably should have) by now. If China does become the largest economy, it is possible for Western hegemony to remain. After all, the Western bloc is larger than the Chinese bloc. However, it would be significantly more difficult (especially if China strong-armed other Asian countries into agreeing with it). I really can't comment too much on the fall of the US since I really have no idea what type of government system Flonne's free country would be. But the US is slowly falling behind anyways (a great book on this is The Clash of Civilizations-- but it's also hella controversial and may make you throw it at the wall multiple times). Regardless, a revolution would really hurt the US position in the world.