They cannot. See #60.
I'll go with mine, this guys and Hunter's knowledge of economics over yours, thankyouverymuch:
Bernanke Again Raises China Currency Policy
Fed Chairman Ben Bernanke has again given ammunition to critics of Chinas trade policies.
In testimony to Congress Thursday, Bernanke said he was worried about the size of the U.S. current account deficit, and a higher Chinese currency would help redress that.
Bernanke
Its the second time Bernanke has cited the impact of Chinas currency policy on trade imbalances. In the text of a speech in China in December, he called Chinas policy of pegging the yuan to the dollar an effective subsidy which aids Chinese exports. He omitted the word subsidy when he delivered the speech, but said this week he stands by the text.
By contrast, both the White House and the Treasury Department, in urging China to let the yuan float, have avoided tying that to the enormous trade surplus China runs with the U.S. Instead, they have emphasized that letting the yuan rise would be in Chinas best interest. The White House Economic Report of the President, released Monday, even suggested that Chinas heavily managed exchange rate has had no impact on trade flows. Chinese intervention does not systematically change the relative real prices between the United States and China, the report said. If prices are unaffected, then neither would imports or exports.
To be sure, Bernanke told Congress that the principal benefits of loosening the exchange rate would be enabling China to have an independent monetary policy, and to reorient its economy towards domestic consumption and away from exports. But in addition, he said, yuan appreciation and flexibility would make some contribution to helping us to rebalance the current account deficit we currently have.
http://blogs.wsj.com/washwire/2007/02/16/bernanke-again-raises-china-currency-policy/