It might be preposterous in this, the year of Trump, to even think about conservatism as an intellectual movement. Trump’s unexpected rise seems to lay bare a simple fact — that conservatism has not only lost the battle of ideas but ceded the terrain of sophisticated thought altogether.

But a deeper understanding of the intellectual currents that have coursed beneath modern conservatism is essential to explaining why those currents now appear to have dried up. Ever since George W. Bush declared Jesus Christ to be his favorite political philosopher,Republican presidential candidates have competed in a sort of anti-intellectual sweepstakes, each seeking to outdo the others in disavowing science, higher learning, and any deliberate cultivation of the mind. How did a movement once defined by intellectual intensity become so hostile to ideas?

As it happens, the year of Trump also marks the 40th anniversary of a book that has done as much as any work to explain American conservatism. In 1976, a Harvard Ph.D. named George H. Nash came out with The Conservative Intellectual Movement in America Since 1945. The book may not be well known to general audiences. But for scholars then and now, it has been foundational, one of those rare works that didn’t just say something new but opened up an entire field of study.

Nash presented an influential portrait of conservatism as a river fed by three tributaries of thought: Christian traditionalism, anti-Communism, and libertarianism (or classical liberalism). Although each could be rendered as a popular impulse or unthinking reflex of the mass mind, Nash insisted that all three were fundamentally intellectual traditions, nourished by a cast of characters who deserved both respect and extended study, among them James Burnham, the former socialist turned anti-Communist; Friedrich Hayek, the Austrian classical economist; and Russell Kirk, America’s answer to Edmund Burke. In Nash’s telling, these were the men (and they were almost all men) who created conservatism in the postwar years. 

Where is conservatism today? Once an anguished response to war and chaos, religious traditionalism has become just another sort of identity politics; anti-Communism informed by classical liberalism is now recrudescent nativism; and countercultural libertarianism has hardened into market fundamentalism. The evolution has reached its apogee in Donald Trump, a man singularly devoid of ideas and proud of it. To be sure, classic conservative thinkers persist, but their voices are dim, like light from a dying star. ...