Sarah Palin

As of 2006/7 the European Union is the world's largest economy (just), not the US.

The EU's GDP hit $14.5 trillion and the U.S's production came in at $13.9 trillion. Most analysts agree that China will be the world's largest economy within 10-15 years, putting the U.S third (or possibly 2nd depending on the EU's performance).

The EU isn't a country, but yes, the EU now has a slightly larger economy, primarily because it keeps absorbing bits of Eastern Europe. I daresay that if you compare NAFTA and the EU, NAFTA will be bigger (though I don't have numbers to hand).

As for China - well, I said there were credible challengers now. But Chinese growth has been so dependent on US and EU consumption that I think it will be significantly longer than 10-15 years before the Chinese can actually mount a meaningful challenge to US economic hegemony - they have a lot of work to do at home, first, and they're rather dependent on the rest of the world getting rich enough quickly enough to buy more of their goods.