"A National Public Radio (npr.org/blogs) Mara Liasson Best Book of the Year for 2010" James T. Kloppenberg is the Charles Warren Professor of American History and chair of the history department at Harvard University. His books include Uncertain Victory: Social Democracy and Progressivism in European and American Thought, 1870-1920; The Virtues of Liberalism; and A Companion to American Thought. A leading intellectual historian traces the origins...