What causes a generation of intellectuals to switch its political allegiances--in particular, to move from the opposition to the mainstream? In U.S. history, it is the experience of the "Old Left" intellectuals, who swung from avowal of socialism or Communism in the 1930s to apology for American liberalism in the 1950s, that raises this question pointedly. In this highly original and broadsweeping study, Howard Brick focuses on the career of Daniel...