In the late twentieth century the effectiveness of government in the United States has come under profound strain. The burdens of superpower status have imposed contradictory demands on the populace, testing the national consensus on the ends of government at home and the goals of American power abroad. Partisan competition for the loyalty of the electorate, meanwhile, has eroded popular understanding of the founding principles of the republic. «You cannot», said Lincoln, «fool all of the people all of the time.» But today the vitality of the American republic depends as never before on the refusal of its citizens to fool themselves.