I love this piece by Cass Sunstein. In it he limns the history of the Alger Hiss case, in which a paragon of 20th century liberalism was revealed to be a Soviet spy. Hiss couldn’t have been any more of a mainstream liberal:
Hiss’s career (including after he was accused of being a spy and after being in jail) included stints at: the State Department, the United Nations, clerking for Oliver Wendell Holmes Jr, the Justice Department, some Senate Committees, the Carnegie Endowment for International Peace, and – naturally – Harvard Law.
During and after the revelations, all the other organs of mainstream liberalism continued to defend Hiss’s actions.
And Sunstein’s conclusion is that the Tea Party is irrational to distrust liberals.
There’s a better discussion about the article here.