Paul Berman has written a beautiful primer on totalitarianism—of the left and the right, East and West—and observed that it invariably contains a genocidal, and even suicidal, dimension. He notes that the twentieth century was a great incubator of "pathological mass movements"— political movements that "get drunk on the idea of slaughter."32 He also points out that liberal thinkers are often unable to recognize these terrors for what they are. There is indeed a great tradition, in Berman's phrase, of "liberalism as denial." The French Socialists in the 1930s seem to have had a peculiar genius for this style of self-deception, for despite the billowing clouds of unreason wafting over from the East, they could not bring themselves to believe that the Nazis posed a problem worth taking seriously. In the face of the German menace, they simply blamed their own government and defense industry for warmongering