Mitt Romney's theory goes that by buying U.S. currency (so far they have accumulated around $3 trillion) and treasuries (around $1 trillion) on the open market, China keeps demand for the US dollar high. They can afford to buy and hold so much US currency due to their huge trade surplus with America, and they buy US currency roughly equal to this surplus. To keep this pile of dollars from increasing the Chinese money supply, China sterilises the dollar purchases by selling a proportionate amount of bonds to Chinese investors. Supposedly by boosting the dollar, yuan-denominated Chinese goods look cheap to the American (and global) consumer. What Romney is forgetting is that every nation with a fiat currency is to some degree or other a currency manipulator. That’s what fiat is all about: the ability of the state to manipulate markets through monetary policy. When Ben Bernanke engages in quantitative easing, or twisting, or any kind of monetary policy or open market operation, the Federal Reserve is engaging in currency manipulation. Every new dollar that is printed devalues every dollar out in the wild, and just as importantly all dollar-denominated debt. So just as Romney can look China in the face and accuse them of being a currency manipulator for trying to peg the yuan to the dollar, China can look at past U.S. administrations and level exactly the same claim — currency manipulation in the national interest.