IT TAKES A LOT to get Alan Greenspan on an airplane these days. He has enough to do at home: tend to the economy, develop monetary policy that can cope with the profligate fiscal policy concocted by the president and Congress; and begin packing his office so that he can be out the door when his term expires at the end of January. But this week he is off to Beijing.

The Treasury was scheduled to deliver a report to Congress this month in which it would have to decide whether to name China as a currency manipulator. Since it is clear to everyone that China is artificially depressing the value of its yuan, this presents Treasury Secretary John Snow with a problem. If he brands China a currency manipulator, congressmen who have been calling for a 27.5 percent tariff on all imports from China–their estimate of the extent of the undervaluation of the yuan–will pounce. Chuck Schumer, the New York senator who could not be convinced that John Roberts is qualified to serve as chief justice, would like nothing better to add to his credentials as a Bush-tormenter by leading the charge for protection from Chinese imports.