Bradley C.S. Watson is professor of politics at Saint Vincent College, where he holds the Philip M. McKenna Chair in American and Western Political Thought. His books include “Living Constitution,” “Dying Faith: Progressivism and the New Science of Jurisprudence,” “Progressive Challenges to the American Constitution: A New Republic,” and, most recently, “Progressivism: The Strange History of a Radical Idea,” from which this essay is adapted.