The United States has become dangerously dependent upon the whims of foreign investors, to help finance its massive budget deficits -

monetary base rise - money printing - inflation

- and prevent a surge in long-term interest rates, which would have a devastating impact on the US economy.

If bond or currency traders detect that big investors in US government bonds, such as China, Japan, OPEC, Russia, and Brazil, have ceased to buy US Treasury debt, or worse yet, are becoming net sellers, it could spark a sharp slide in US Treasury notes, sending yields sharply higher, and ignite a free-fall in the US dollar.

http://www.seekingalpha.com/article/138966-is-the-u-s-dollar-headed-for-a-mighty-crash-part-i?source=quickread

..right We all know this.