The current financial crisis has its roots in Greenspan's decision to keep interest rates very low in 2002 and 2003 to head off the danger of a deflation-induced double-dip recession, and his subsequent decision that the costs of cleaning up after a housing bubble were likely to be less than the costs of the high unemployment that would be generated by a preemptive attempt to pop a housing-speculation bubble. Two years ago, I would have said that Greenspan's judgment here was correct. Six months ago, I would have said that his judgment was probably correct. Today -- in the middle of the largest nationalizations in history -- I can no longer state that Greenspan made the right calls with respect to the level of interest rates and the housing bubble in the 2000s. (emphasis mine)
From Brad DeLong.
This is the nice thing about economics (and blogging) being a spectator sport - we get to be right all the time.