An intellectual history of American conservativism since the New Deal. The New Deal fundamentally changed the institutions of American constitutional government and, in turn, the relationship of Americans to their government. Johnathan O'Neill's Conservative Thought and American Constitutionalism since the New Deal examines how various types of conservative thinkers responded to this significant turning point in the second half of the twentieth century. O'Neill identifies four fundamental transformations engendered by the New Deal: the rise of the administrative state, the erosion of federalism, the ascendance of the modern presidency, and the development of modern judicial review. He then considers how various schools of conservative thought (traditionalists, neoconservatives, libertarians, Straussians) responded to these major changes in American politics and culture. Conservatives frequently argued among themselves, and their responses to the New Deal ranged from adaptation to condemnation to political mobilization. Ultimately, the New Deal pulled American governance and society permanently leftward. Although some of the New Deal's liberal gains have been eroded, a true conservative counterrevolution was never, O'Neill argues, a realistic possibility. He concludes with a plea for conservative thinkers to seriously reconsider the role of Congress—a body that is relatively ignored by conservative intellectuals in favor of the courts and the presidency—in America's constitutional order. Conservative Thought and American Constitutionalism since the New Deal explores the scope and significance of conservative constitutional analysis amid the broader field of American political thought.