Is it likely that a fresh look at the economic data had Ben Bernanke and Don Kohn doing a sharp about face on the balance of risks to the economy? Given the speed with which their change in policy was communicated, catching a fellow Fed head flatfooted in spouting the party line the day before, it seems more probable that something on the order of one or more major players started to spew smoke from the cracks in their mark to moonbeams calculations, and Hank made that call to the Professor.
We obviously don't know, but suspect this revelation was connected with a subprime contagion affecting the derivatives markets. If derivatives are Weapons of Mass Destruction, then the Credit Default Swaps market is the H Bomb. Credit Default Swaps, if they start unwinding, can develop a chain reaction that will take out a fair chunk of the real economy, in addition to two or three big name corporations.
Subprime had the Fed a little concerned; CDS has them staring into the abyss and shitting their pants. Aren't you glad we have men so familiar with the mistakes the Fed made in 1929 to 1932 with regard to Fed Policy? We wish they had at least audited the courses covering the Fed's mistakes form 1921 to 1929. Sure, they are the experts; we're just concerned that they may be preparing to fight the last war.