Ever since Ronald Reagan's election in 1980, the strength of American conservatism has largely confounded historians and intellectuals. Before then, a generation of influential scholars claimed that liberalism was the core of all American political thinking and suggested that it always would be. Well into the 1970's, many observers wondered whether a Republican Party that allied itself with the conservative movement could long survive. History has, to say the least, disproved these judgments. Yet many prominent liberals continue to see contemporary conservatism as a rhetorical smoke screen intended to deceive the masses - even as conservatives often trace their movement...