Think of Wen as a proxy for the Chinese government — particularly those parts of it that have supplied the U.S. with an unprecedented amount of credit over the past eight years. If cheap credit was the crack cocaine of this financial crisis — and it was — then China was one of its primary dealers. China is now the largest creditor to the U.S. government, holding an estimated $1.7 trillion in dollar-denominated debt. That massive build-up in dollar holdings is specifically linked to China’s efforts to control the value of its currency. China didn’t want the renminbi to rise too rapidly against the dollar, in part because a cheap currency kept its export sector humming — which it did until U.S. demand cratered last fall.