“In the United States at this time,” the critic Lionel Trilling wrote in 1950, “liberalism is not only the dominant but even the sole intellectual tradition.” Conservatives and reactionaries, Trilling added, had no ideas, only impulses—“irritable mental gestures which seek to resemble ideas.” Whether the point was true in mid-century America—the reactionary writer Richard M. Weaver published Ideas Have Consequences, an attack on the modern West, two years before Trilling’s The Liberal Imagination—today it is obviously false. For the past decade or more, the intellectual energy in American politics has been on the right. In Furious Minds: The Making of...