The White House announced its reappointment of Ben Bernanke, chairman of the Federal Reserve, the nation's central bank. He deserves it.

He was the No. 1 player in the world in avoiding another Great Depression. The financial collapse last year was the most extraordinary capitalistic event in 80 years. Bernanke was slow to recognize its severity, and the Fed under Bernanke could have done more to prevent it in the first place. He became chairman in early 2006, when there was still time for Fed regulators to stop much of the mortgage madness.

But if the Fed is to blame for the meltdown, most of the burden falls on Bernanke's predecessor, Alan Greenspan. Bernanke was the guy who steered the rescue between the Bush and Obama administrations. He took what really might have been a grievous, decade-long slough and turned it into what we have today: A severe recession, with employment pushing 10 percent, continuing massive job loss and a hugely uncertain fiscal situation for the country. We'll take it.

Part of the problem with evaluating Fed chairman is that what they sow often doesn't get reaped for years and years. People thought Greenspan was doing a wonderful job until after he left, when the damage from creating a money-bubble with lack of regulation became clear. Bernanke has created another money bubble, and his legacy will rest on how skillful he is at deflating it without terrible effects. Bernanke's expertise was in preventing a Depression. He knows far less about how to execute an exit strategy after bailing out the economy because nobody has done it successfully in history. Still, I don't see anybody else out there who seems more likely to succeed.

Barney Frank made a comment that has been widely quoted on blogs recently, on the difference between politicians and economists:

Not for the first time, as an elected official, I envy economists. Economists have available to them, in an analytical approach, the counterfactual. Economists can explain that a given decision was the best one that could be made, because they can show what would have happened in the counterfactual situation. They can contrast what happened to what would have happened. No one has ever gotten reelected where the bumper sticker said, "It would have been worse without me." You probably can get tenure with that. But you can't win office.