From the Hamiltonian-Jeffersonian split over English and French policy in the 1790s to the Republican-Democratic clash over Haitian policy in the 1990s, Americans and foreign observers have been troubled--and often exasperated--by the extraordinary influence of U.S. domestic politics on matters of vital national security. Some critics, including Alexis de Tocqueville, concluded--that America's democratic system would cripple the effective and efficient...