The left got what it wanted in 2008: a liberal president with a sweeping agenda and big Democratic majorities capable of enacting it. The result has been a great and failed experiment in progressive politics and governance. In due course, one hopes, the left will absorb some lessons--but for now, they seem to be suffering a nervous breakdown.
That is one way to understand why so much of the liberal establishment is rallying behind Krugman's Army, as the "Occupy Wall Street" protests are known. Everything they believe in has failed, so they are turning nihilistic.