Democracy is a continuous revolution. April 9, 2003, was Liberty Day for Iraq, the day on which one of the foulest of the 20th-century tyrannies was finally destroyed. The liberation of Baghdad was greeted with celebration as well as looting, and by ill-concealed dismay in Paris, Berlin, Moscow and the left-wing British press. It was unquestionably a victory for the United States, not only for the American forces, but also for the American model of society. The United States has for more than a century been the engine of global liberation. Historical processes have no clear-cut point of origin, but...