American politics has devolved into a grim battle between two approximately equal-size armies in a take-no-prisoners culture war. In 2000, those armies fought to a near-draw--out of more than 100 million ballots cast, the presidency of the United States hinged on a breathtakingly slim 537-vote margin in Florida. Four years later, despite the occurrence of a recession, two wars, and a devastating terrorist attack on American soil, the two adversaries...