The US is, and has been, living well beyond its means, borrowing to finance consumption. This year, for example, we will run a current account deficit of about a trillion dollars, or $3000 per American. Two factors have conspired to make this happen: the suicidally reckless economic policies of the Bush administration and China's determination not to let its own trade be balanced.
The US is the classic profligate, borrowing and spending like crazy, while China, Japan, and expecially the Gulf states play the role of the irresponsible banker willing to keep lending no matter what.
Bartender: That damn drunk keeps running up his tab and never paying.
Customer: Why don't you cut him off?
Bartender: I can't afford to. He'…