He was arguably the most powerful man in Washington for more than 18 years, but former Fed Chair Alan Greenspan waited until retirement to finally come out in favor of a gas tax. Writes Daniel Gross in the NYT:

As a rule, Mr. Greenspan, a Republican by temperament and background who was reappointed twice by Bill Clinton, adhered closely to Republican orthodoxy on taxes: the lower the better. Mr. Greenspan was hardly a proponent of raising taxes on energy to encourage conservation, a policy prescription generally associated with the politicians and economists of the left.

Until now. In late September, as he spoke to a group of business executives in Massachusetts, a question was posed as to whether he’d like to see an increase in the federal gasoline tax, which has stood at 18.4 cents a gallon since 1993. “Yes, I would,” Mr. Greenspan responded with atypical clarity. “That’s the way to get consumption down. It’s a national security issue.”

Want to bet Ben Bernanke will wait until retirement before he comes to the same sage conclusion?