No, really:

President Barack Obama, calling current deficit spending “unsustainable,” warned of skyrocketing interest rates for consumers if the U.S. continues to finance government by borrowing from other countries.

“We can’t keep on just borrowing from China,” Obama said at a town-hall meeting in Rio Rancho, New Mexico, outside Albuquerque. “We have to pay interest on that debt, and that means we are mortgaging our children’s future with more and more debt.”

Holders of U.S. debt will eventually “get tired” of buying it, causing interest rates on everything from auto loans to home mortgages to increase, Obama said. “It will have a dampening effect on our economy.”

via Obama Says U.S. Long-Term Debt Load ‘Unsustainable’ (Update2) - Bloomberg.com.

He doesn't seem to be acting as if he believes it, though.