"The left in Europe arises out of a more traditional class structure, and the left parties there were formed on the basis on those class divisions. Most European countries had feudal societies before they transformed into nation-states. When those societies became capitalist, they retained many of the old divisions both in terms of people's consciousness and in terms of the new social structure. Peasants and lords became workers and employers. So, the parties there tended to fall along class lines much more than in the United States, and people growing up on either side of the class boundary fueled the movements on the left. Even though the differences between the labor or socialist parties and the centrist or right-wing parties have diminished over time, the vision of a socialist society is still alive in many European countries. In America, however, socialism and communism were never more than marginal beliefs."
Mandy Van Devin in Salon talks with Michael Kazin about his new book, American Dreamers: How the Left Changed a Nation.