Jonathan Lethem’s new novel, “The Feral Detective,” captures the florid horror that followed the 2016 election in a tone that is both wisecracking and stricken. Photograph by Todd Heisler / NYT / Redux

Jonathan Lethem’s novel “Motherless Brooklyn,” which won the National Book Critics Circle Award for fiction in 1999, is a noir tale of mobsters and P.I.s that slips its suit to become a startling rumination on words and brains and the cords that correlate disparate ideas, sounds, and people. The main character, Lionel Essrog, works for a detective agency in the mostly benign thrall of a petty-crime lord named Frank Minna, who is murdered as the book opens. Lionel sets out to solve the mystery of his boss’s death. He has Tourette’s syndrome, and the novel lingers over the poetry of his logorrhea, how a word piped into his ear will set other words skittering from his mouth: triage, arbitrage, sabotage. Tourette’s lends itself to detective work, Lethem implies. It conjoins elements, weaves meaning, deduces the shape of the thing. Tourette’s is a way of caressing the world with language. “Motherless Brooklyn,” with its interest in connectivity, might be read as a celebration of “consensual reality,” that which we create together and hold between us, “fragile and elastic . . . like the skin of a bubble.”

Lethem’s newest book, “The Feral Detective,” begins in January, 2017, five days before the Inauguration of President Donald Trump, and consensual reality has popped. Or, rather, it has halved into two vesicles: red and blue America. The protagonist, Phoebe Siegler, is a New Yorker with Harvard, NPR, and the Times on her résumé; she unwinds by reading Elena Ferrante at a coffee shop. The rise of the “Beast-Elect” so disillusions her that she quits her job and breaks for the California badlands, where her friend’s teen-age daughter, Arabella, has gone missing. Phoebe is searching for Arabella, but perhaps she is also in search of a story: “Sew a Pepe the Frog medallion onto your backpack, young lady,” she thinks to herself. “Go seduce the unspeakable and hairy, then report back.” Phoebe enlists the help of Charles Heist, the feral detective of the title, a laconic and alluring Philip Marlowe type who has ties to the local community of runaways. Driving into the wilderness, the pair is swept up in a power struggle between two tribes of survivalists: the Rabbits (gentle, hippie-ish) and the Bears (ex-cons and bikers, tattooed, toxically masculine). Lethem seems to pull from “Mad Max” and “True Detective”—primordial dramas unfurling against desert voids. “Here in the desert we were enclosed in an unboundaried thing that apocalypse might be the word for,” Phoebe says. At one point, amid a gory ceremony to choose the next Bear King, Phoebe wades into the blood and muck to scream, “DO YOU EVEN KNOW WHAT’S GOING ON, YOU STUPID FUCKING ASSHOLES? DID YOU FUCKERS EVEN VOTE?”

A wonderfully menacing passage in this ridiculous book evokes the primal strangeness of the male id rising up to eat the world. Here is Solitary Love, the incumbent Bear liege, preparing to fight Heist:

His look and manner were a correction to what the nameless boy had called the chimerical dream of civilization. Seeing the Bear King stride into the flickering stony rink, it wasn’t even so much that all human charity and feeling . . . had been dispatched, rendered null—well, it was that, but it was more, too. Seeing him, you kind of wished it to be. Bring the flood. It was at this moment I did the math and realized that . . . Barack Obama was no longer president.

Here, Lethem captures the florid horror and the weird, nihilistic sense of possibility that arrived in the immediate wake of Trump’s election. Elsewhere, his tone is both wisecracking and stricken; its serious and comic notes cancel each other out, and what’s left is a cartoon despair.

“The Feral Detective” is one of the first pieces of fiction to address the Trump Presidency, not obliquely (as in, for instance, Curtis Sittenfeld’s “You Think It, I’ll Say It”) but directly, inconsolably, furiously. Trump is “the monster in the tower”; the television that “had elected itself.” Lethem channels the unprocessed trauma of January, 2017—its stark existential bewilderment. (In an interview, the author cited J. R. R. Tolkien, the bard of vast vistas, as an influence.) “The Feral Detective” runs for nearly the same number of pages as “Motherless Brooklyn,” but it registers as much longer, both draggy and strained. It’s not just that the novel is loaded with lazy signifiers (Phoebe invokes the glories of “surefire viral content” and yearns “for my cubicle, for another Tinder date at the Bourgeois Pig”); it’s that Charles, her aide-de-camp and eventual lover, never lives on the page—he’s a thousand-mile stare, a leather jacket—and that Phoebe’s incessant, effortful banter is as repellent as Lionel’s was irresistible. “This discovery certainly did float my boat,” she says. “Talk to me in the King’s English, Tarzan, just like they taught you in finishing school,” she says. The Lethem of 1999 traffics in clean, taut, suggestive images. (“I could feel his anger unfolding, smooth as a fresh deck of cards.”) The 2018 Lethem attempts to transcend clichés via different, worse clichés. “I’ve endured my share of male strip-you-bare eyework,” Phoebe reflects, when she and Heist first size each other up, “but this was more existentially blunt, souls meeting in a sunstruck clearing.”

Lethem’s strategy for writing an “authentic” woman appears to consist mostly of emphasizing her sexuality. (“So I took my phone to a bakery and . . . hoped for some amusing college student to hit on me,” Phoebe recounts.) The author has stated that he was already “trying to talk about a crisis in gender relations” with his novel before Trump was coronated; afterward, he recommitted to the theme. The book suggests that men writ large are dangerous and atavistic (“stuck in the past”), whereas women writ large are flibbertigibbet clowns for whom nothing is sacred—more of a step sideways from Trumpism than a step forward.

The real missing-persons case here is a meta one: Where has the sly, surprising Lethem gone? Phoebe perhaps expresses the author’s political frustration, his verbal playfulness, but the Essroggian inspiration has fled, as if an unerring gumshoe had been standing at the top of some steps when a masked figure with orange hair and a long red tie hit him over the head with a cudgel. “So many detectives have been knocked out and fallen into such strange swirling darknesses,” Lionel says, “such manifold surrealist voids.” The same fate has seized the novel, and us, trapping us in an America that is no hazy nightmare but our home.

A previous version of this post misstated the name of the character Charles Heist.