When China's prime minister, Wen Jiabao, expressed concern about the ability of the US government to repay its bonds, his comments prompted headlines everywhere. The newspapers were filled with gloomy warnings that China may no longer be willing to buy up US debt, which supposedly would have dire consequences for us all.
Unfortunately, too little thought was given to what these "dire consequences" might be, and who would end up suffering them. Suppose that China stops buying US government debt. That would mean that the dollar would plummet in value against the yuan. Chinese imports would suddenly become much more expensive for consumers in the United States, making domestically produced items far more competitive....The opposite would happen in China. Goods and services made in the United States would suddenly be much cheaper... The reduction in imports from China and the increase in exports would substantially improve our balance of trade.
In other words, if Wen was threatening to stop buying dollar-denominated assets and therefore let the yuan rise against the dollar, he was threatening to do exactly what the US government has been demanding that China do. He will stop "manipulating" China's currency – meaning he will stop deliberately intervening in the market to keep the yuan's value from rising.
http://www.guardian.co.uk/commentisfree/cifamerica/2009/mar/30/us-economy-china-debt