There’s a sort of ideal figure that conservative intellectuals conjure when they want to argue about the essence of their ideology. This figure is a dreamy quietist of peaceable disposition, who savors apolitical friendship, nurses a skeptical outlook, and looks to an anti-theoretical politics of homey tradition and humane, but chastened, sentiment to guide him. The political scientist Corey Robin argues in his 2012 book, “The Reactionary Mind,” that this ideal is more like a myth. Conservatism, Robin says, is always inherently a politics of reaction—usually also populist, often also violent. From Robin’s argument, we could predict that a conservative party would be unlikely to nominate the idealized conservative as its standard-bearer, but that it would absolutely yoke itself to a populist nut job like Donald Trump.

Robin’s argument about why this happens is a little too sweeping at times, too reliant upon convenient factoids for its historical-theoretical linkages. For example, he dubiously establishes that libertarians are secret heirs to Hobbesian absolutism by noting that the free-market economist Milton Friedman was an adviser to the Chilean dictator Augusto Pinochet. And conservative readers would surely grind their molars on seeing John Calhoun and Ronald Reagan blithely summoned as members of the same political team. By the same token, this bold and maddening connection between a notorious slavery apologist and a beloved Republican provided a polemical charge that was no doubt central in turning the book into an unexpected publishing hit among progressives still energized by the Occupy movement.

Robin establishes the necessary link between conservative and reactionary politics by analyzing the role that the conservative takes in the historical drama of social change, the moment he’s called onto the scene of conflict to defend and vindicate the traditional ways under assault by reformists or revolutionaries. The classic example of such a figure is Edmund Burke, the Irish-British philosopher and parliamentarian who is generally considered the father of modern conservatism. His central text, “Reflections on the Revolution in France,” is at once a broadside against the revolution’s methods and goals and a defense of traditional life.

The core of Burke’s rich conception of tradition is his description and defense of what he calls “prejudice”—by which he means, roughly, the experience and virtue that repose in everyday norms and practices. It’s a lovely bit of sentimental prose, expressing a conception of life that is pleasant to entertain—namely, that our unthought habits brim with the wisdom of generations, that the blacksmith or carpenter or farmer discharging his daily chores is the last expression of a long practice of trial and error, ingenious precisely because this practice partakes of no theory. Prejudice “renders a man’s virtue his habit,” and thus leaves him deeply at home in the swim of time. The past whispers its instructions to him, not via critical reflection or abstract speculation but through the things he’s already doing more or less automatically.

This passage is a favorite of brainy conservatives—and you can see why. Its elegant vindication of tradition is also a pithy meta-critique of progressive rationalism. This critique says that rational social engineering, the sort often pursued by revolutionaries and progressive reformers, can never reproduce the subtle knowledge and virtue captured in tradition. It can only destroy them. But once you put it that way, once you step back and see Burke’s writing as a meta-critical defense of unthought tradition, you start to feel the irony of his situation.

Tradition doesn’t need Edmund Burke until it’s been challenged. But once it has been challenged—by Jacobins, or Bolsheviks, or abolitionists—it is no longer a virtuous bundle of unthought habits by which the past guides the present. It is now an object of conscious defense and nostalgia—the guiding theme in an ideology of loss. The conservative describes the depth and meaning of this loss (to which he has, in his own way, contributed), and then offers some promise of return and restoration.

A recurring oddity of conservative politics, Robin shows, is that the flip side of its nostalgia is a kind of eager futurism—an itch to discard the dead body of tradition, transcend the reformist or revolutionary present, and realize the gleaming future-past or past-future where this longed-for restoration happens. To understand what this means in American practice, you only have to recall the futuristic nostalgia of Ronald Reagan, his deathless slogan: “It’s morning in America.” The name “postmodern conservative” is sometimes given to idiosyncratic thinkers on the contemporary right, but if the dissolution of old social forms is the default modern condition then conservatism, in its embrace of a restorationist future beyond this dissolution, has been postmodern since the French Revolution.

Conservatism, then, is inherently an ideology of reaction. It is so, first, in the obvious sense that it generally flares in reaction to revolution or reform. But, more importantly for the present moment, and more disturbingly, the narrative of loss and promised restoration in conservatism hums with the possibility of violence. Rather than the friendly equanimity espoused as typically conservative by the English philosopher Michael Oakeshott, this is a fighting nostalgia. Indeed, Robin shows, an itch for political battle runs throughout Burke’s writings in a way that is rarely noted by his many defenders (among whom number both conservative writers and liberal academics). And this reactionary pathos continues to flow, through slaveholding Confederates and Italian fascists and supporters of Barry Goldwater.

America is too young and too perpetually roiled to have much of a settled tradition for a conservative to defend, but what it has in the place of tradition is a Constitution. Constitutionalism plays a double role for American conservatism today, five decades after the civil-rights movement. It stands in for the threatened (dead) tradition that conservative politics rises to defend (restore). And it insulates mainstream conservative thought—both sociologically and intellectually—from the uglier populist strains that run through conservative practice. White rabble-rousers might invoke “reverse discrimination” to motivate racist voters, but to conservative intellectuals affirmative action simply violates the plain meaning of the Fourteenth Amendment. The political link to the white rabble-rouser is lamentable but incidental, and irrelevant.

Don’t get me wrong. This is sincere. Conservatives—that is, conservative writers and their more thoughtful readers—are intensely self-aware when it comes to race. They spend more time scanning their inner selves for racist motives than most progressives do, I’d wager. Most are keen to square their idea of conservatism with the broad formalist understanding of racial equality that was encoded in the Civil Rights Act of 1964. It took some work—accepting, for example, that private businesses are also “public accommodations” and that the owners of these businesses do not have an absolute right to say who can and cannot enter—but most, renouncing Goldwater’s opposition to this law, have fit it into their constitutionalism.

But a Trumpist fate lurks even in genteel constitutionalism. “The Reactionary Mind” contains a trenchant (and sometimes unfair) essay on the late Supreme Court Justice Antonin Scalia that shows the close link between Scalia’s originalist jurisprudence and the warlike, reactionary pathos that fuels conservatism deep down. For Scalia, ruling from disciplined constitutionalism, when the prevailing sentiment runs against both discipline and constitutionalism, meant being a prick sometimes—a constitutional hard-ass. But Scalia wasn’t just a hard-ass when it was necessary to defend the Constitution’s original meaning, Robin shows. He celebrated hardness for its own sake and pursued it as an end in itself, sometimes at the expense of his Constitution. When torture came before the Supreme Court, Scalia took to invoking Jack Bauer, from the television show “24,” in oral argument, not so much for Bauer’s tactical wherewithal as for his moral example: a man able not just to endure torture himself but, more importantly, to face the awful truth that he must torture others.