If American diplomacy can seem confusing to foreigners, that is because it partakes of eight different traditions, suggests Pulitzer Prize-winning historian McDougall (Univ. of Pennsylvania; Let the Sea Make a Noise, 1993, etc.) in this perceptive study. The eight traditions that McDougall explores are American exceptionalism, unilateralism, the American System, expansionism, progressive imperialism, Wilsonianism, containment, and global meliorism. McDougall is at pains to correct what he sees as misreadings of the history of American foreign policy. He argues that the hallmark of that policy in the 19th century was not isolationism but unilateralism--in other words, avoiding permanent alliances that could endanger domestic liberty, and intervening only when vital American interests were at stake. McDougall also undercuts revisionist historians' claims that the American acquisition of territory after the Spanish-American War was an imperialist grab, arguing instead that it was a measure taken to prevent foreign attempts to gain bases that could endanger America. He offers particularly trenchant criticisms of Woodrow Wilson for opening the door to messianic foreign interventions, and of Bill Clinton for extolling multiculturalism and diversity at home while having ""no tolerance of them where other countries were concerned."" McDougall agrees with the opposition of Henry Cabot Lodge and Theodore Roosevelt to Wilson's Treaty of Versailles, crediting their opposition more to principled defense of American sovereignty than to implacable partisan and personal opposition to the president. Above all, he convincingly argues that sacrifice for foreign clients, whether through LBJ's global social-welfare schemes or Clinton's appetite for nation-building, has financially and morally bankrupted the US. Not pitched on the epic scale of McDougall's earlier work, this is a subtle, scholarly call to forsake ideology in foreign policy in favor of true national self-interest.