Maybe not entirely faceless, though. One face, sporting a pale forelock, looms large. One name, deployed as a verb, whips and snaps. You know it, I know it: Trump. I’m writing this in rural Indiana, where I’m visiting family. Out the window I can see the neighbor’s house, where a TRUMP flag flies at full-staff. Even a house on a country road can become part of a crowd.

That’s the phenomenon Jeff Sharlet captures in his new book, “ The Undertow: Scenes From a Slow Civil War . ”   Sharlet has spent much of his career covering the intersections of religion and right-wing politics, most famously in “ The Family: The Secret Fundamentalism at the Heart of American Power .” A look at the Christian organization that hosts the National Prayer Breakfast, among other activities both domestic and international, “The Family”   found new life during the early Trump administration, when a documentary based on the book aired on Netflix.

Trump, and Trumpism, benefited more than anyone could have guessed from this fusion of personal faith and political action. Sharlet has chronicled that rise in his dispatches for Vanity Fair, traversing the country to visit the faithful. “The Undertow” gathers that writing, along with some new material, to form a travelogue that tarries with furious people in forgotten places, all of them convinced that civil war of some sort is in the offing. This marks a difference between his earlier work on “The Family,” which involved deep dives into the organization’s history and hierarchy, and “The Undertow.” To put it in religious terms, one could say he’s turned his attention from the pulpit to the congregation. Less the leaders and more the crowds, whether physical or virtual, sitting in pews or staring into screens.

It’s almost too easy to mock those who join such gatherings. I know I’m guilty of that. But Sharlet urges the reader to take their fantasies seriously, as they have produced consequences that are all too real. The realest, of course, arrived   on Jan. 6, 2021 . At the time, the storming of the U.S. Capitol felt unbelievable. Reading “The Undertow,” it feels inevitable.

A hipster megachurch in Miami fills the sanctuary to capacity with a message of prosperity, and nothing else. A men’s rights conference held outside Detroit draws a host of men, and a surprisingly formidable contingent of women, to discuss the supposed dangers of feminists entrapping men with false accusations of sexual assault. The women’s presence highlights a running theme of the book: Look at these crowds, and you will see faces you never expected to find there. A bravura sequence finds Sharlet in Sacramento at a rally for Ashli Babbitt, the woman shot and killed by Capitol police on   Jan. 6 . He then journeys across the country, from churches to American Legion posts to Shooters, the now-defunct “open-carry” restaurant owned by Republican Rep. Lauren Boebert of Colorado. Everywhere, from everyone, he hears talk of civil war, the term never quite achieving definition. “When I asked,   civil war , when the believers answered,   civil war , we were speaking in metaphors we could barely comprehend. We were describing a feeling that frightened or exhilarated us: a body coming apart.”

But if a war is coming, even a metaphorical one, what are its terms? What are the grievances these crowds seek to address? Based on the signs waved at rallies and the hashtags gone viral on social media, their complaints include, but are not limited to, immigration, mask mandates, gun rights, gender identity,   abortion . But there’s not even consensus on which of these issues matters most or in what way. One darkly funny scene finds a Trump-flag-waving homeowner in Wisconsin incensed with   the Democrats   for overturning   Roe v. Wade . Anger searching not for a target but a pretext.

Yet Sharlet believes there is a deeper fear, a deeper grievance, roiling beneath the copy-pasted outrage. The underlying cause of this potential civil war is not so different from that of the actual civil war of the not-so-distant past: race.

“They are angry about their own bodies, about how other people’s bodies make them feel,” Sharlet writes about these mostly White crowds. And how do other bodies make them feel? In a word, uninnocent. The very awkwardness of that term suggests the mental gymnastics these crowds struggle to perform. The crowds revere innocence, purity, blamelessness. Ashli Babbitt is transformed from a troubled young woman into a flawless saint, a martyr for the cause of freedom. “Be proud   White   Americans!” Babbitt’s mother exhorts the crowd at a rally for her daughter. Proud they are innocent of racism, prejudice, guilt. Yet even the presence of non-White people is a reminder of the bloody, guilt-ridden history of the land they live on. None can escape it, no matter how hard they might try, no matter how much of the past they forget.

If “The Undertow” lacks anything, it’s a sense of the grim economic landscape. Prices are going up everywhere while wages are going down. Many of the people at these crowds — the “beautiful ‘boaters,’” as Trump so appositely   calls them   — are quite prosperous, yet they live in the least-prosperous areas, the exurbs and the small towns of flyover states. Such proximity to immiseration probably contributes to the sense of desperation on display at these gatherings. The blight is at the door, and they raise their flags to keep it at bay.

But that’s a minor quibble. I deeply appreciate Sharlet’s mythic-religious approach and how it enables him to capture what other journalists miss. Data can tell only half the story, and usually the half that’s less interesting. Add to that the book’s welcome ambition, both as journalism and literature. This is no mere compilation of bullet points. This is journalism-as-art, attempting to capture the mood of the nation at this fraught moment, so that others in the future may know how it felt to live through the present. Hopefully there will still be readers then.

Adam Fleming Petty is a writer in Grand Rapids, Mich.

Scenes From a Slow Civil War

By Jeff Sharlet

W.W. Norton. 337 pp. $28.95