Most Americans assume that U.S. foreign policy is determined by democratically elected leaders who define and protect the common good of the citizens and the nation they represent. Increasingly, this conventional wisdom falls short of explaining the real climate in Washington. Well organized private-interest groups are capitalizing on Americans' ignorance of world politics to advance their own agendas. Supported by vast economic resources and powerful lobbyists, these groups thwart the constitutional checks and balances designed to protect the U.S. political system, effectively bullying or...