Sen. Elizabeth Warren played to a friendly crowd when she visited Brooklyn last week. The rally at King’s Theatre on Flatbush Avenue — an ornate people’s palace kind of joint with fleur de lis in the molding and vaudeville ghosts in the rafters — was a 4,800-person shot in the arm for her campaign, which had been flatlining of late. Julián Castro, young, Latino and recently out of the presidential race, had just endorsed Warren and there seemed to be a sense in the air — with a heavy hint from the mass-produced “We ❤ Julián” signs circulating — that the campaign was looking for a little good news out of the evening. The crowd scanned as largely young and professional, and a little girl sitting just in front of me waved another sign: “I’m running for president because that’s what girls do.”

Just under a week later, the Warren campaign would be at war with Sen. Bernie Sanders over Warren’s claim that Sanders told her in a private 2018 meeting that he didn’t think a woman could win the 2020 presidential election. This salvo from Warren’s camp was seen as a response to reports that talking points for Sanders volunteers characterized Warren as the choice of “highly educated, more affluent people,” a demographic both key to Democratic electoral success and associated with Hillary Clinton’s supposed out-of-touch elitism. Within a few hours, what had been a cold-war battle to define the left wing of the Democratic Party had gone hot. The handshake-that-wasn’t between Sanders and Warren at Tuesday night’s debate seemed to inflame tensions even more.

What’s curious, though, is that the rift isn’t over policy particulars. The Warren vs. Sanders progressivism fight seems to be more stylistic, an unexpectedly tense class war of sorts within the broader progressive class war. Should progressive populism be wonky and detail-oriented and appeal to college-educated former Clinton voters? Or a more contentious outsider assault on the powers-that-be from the overlooked millions of the middle and lower-middle class?

The groundwork for more open hostilities was perhaps laid at the start of last weekend with some numerical tinder. As I boarded a plane for Des Moines, Iowa, on Friday night, I scanned the results of the just-released Des Moines Register poll. The survey showed Sanders leading in the state with 20 percent of the vote, a notable shuffle in the race from the last poll from that pollster, which showed former Mayor Pete Buttigieg in the lead and Sanders scrapping for third place with former Vice President Joe Biden. Saturday afternoon I found myself in Newton, Iowa, listening to Larry Hurto, 68, reciting the full results of the poll to me from memory as he waited for Sanders to arrive at a rally. With Sanders, Hurto told me, “What you see is what you get.” Kim Life, 60, told me she’d voted for Clinton in 2016 but felt that, this time around, Sanders was the man for our times. “Things in the world are so unstable,” she said. “He hasn’t changed in 40 years.” Warren, she told me, was more influenced by corporate America than she let on.

Variations on this theme — Sanders as credible progressive curmudgeon and Warren as vaguely deceptive opportunist — popped up as I followed Sanders across the state. America is a country whose politics are pheromonal; voters are largely attracted to certain candidates not for their policy positions but for the cut of their jib or the familiarity of the story at the heart of their self-mythology. And among the Sanders-committed, there seemed to be a sense that the candidate’s famous frankness was his greatest asset — and it could well be with certain groups.

The other part of the controversial Sanders campaign talking points on Warren was that her supporters — the wealthy, well-educated ones — would already “show up and vote Democratic no matter what … she’s bringing no new bases into the Democratic Party.” At his rallies, Sanders was putting his electability foot forward — supporters waved “Bernie beats Trump” signs while he spoke. In November, The New York Times polled battleground state voters and found that persuadable, white working-class voters had policy views that aligned with some Sanders/Warren proposals, but “by a margin of 84 percent to 9 percent, they say political correctness has gone too far. They say academics and journalists look down on people like them.” Nonwhite persuadable voters supported systemic change candidates and single-payer health care, but 50 percent approve of Trump, a man known for pushing the boundaries of correctness, political or otherwise.

The anti-political-correctness voters and Trump-approvers are perhaps the demographics where Sanders has the greatest chance to make inroads. While his trademark directness isn’t anti-PC, it’s of a sympatico strain, in a way: “I don’t care what you think, I’m going to say and do what I please.” The Sanders brand is based entirely on that slippery, overused quality that politics so prizes: authenticity. He has believed in the same things for decades and advocated for them in the same polemical style. Even his heavy Brooklyn brogue remains unchanged despite his having left the borough in the ’60s. It speaks to being from a place.

Of course, Warren still has the flatness of the plains in her voice, but maybe that’s harder to pick out of the American pantheon of dialects and accents. Plus, the patina of Harvard elitism might stick more to a woman, with voters being more apt to see her as overly liberal in a cultural sense rather than an economic one — ironic, in Warren’s case, given that the cornerstone of her candidacy is radical economic reform. Her tightly constructed, loosely delivered stump speech in Brooklyn — Warren likes to pump her fists while she talks and bend down as if she might jump across a stage — was adept at connecting her famous plans together as a bid for “big, structural change.” Whatever issue brought people to the rally, Warren said, “I guarantee it’s been touched by money.” It was a solutions-oriented 45-minute verbal march; though, of course, both Warren and Sanders know that unless Democrats win the Senate in 2020 (unlikely) and hold onto the House, much of their potential agenda as president would be stymied from the get-go.

But each know that rhetoric wins the day. While they share so many policy goals, it’s obvious their appeal is somewhat divergent. There is certainly a gap between the demographics of Sanders and Warren supporters. According to FiveThirtyEight/Ipsos polling, conducted using Ipsos’s KnowledgePanel, about 34 percent of people considering voting for Warren’s have household incomes of over $125,000, compared to around 22 percent of potential Sanders supporters. And Warren’s potential backers are particularly skewed toward college-educated Democrats, while people considering Sanders and Biden are more evenly distributed across education levels.

Sanders is not wrong in pointing out that Warren’s populism — and make no mistake, it is that; she does her fair share of billionaire-bashing — has resonated with a different audience than his. In part, it’s because her packaging of populism is meant to extend an ideological hand to the establishment Democratic voters who cottoned to Clinton in 2016 but regretted, perhaps, their inability to see that the country was ravenous for system-busting talk. She scratches the itch of big ’ole change but understands that the Democratic Party is filled with people who are still comfortable within the system, even if they have intellectual critiques of it.

Sanders’s selling of populism is conscious of its place in the sweep of progressive history. In Iowa, he talked about how not so long ago, public education was seen as a radical idea and cited the aphorism, “It always seems impossible until it’s done,” to explain the mental block the country could overcome to accept Medicare for All.

On Saturday evening, Sanders held a rally in Davenport that opened with performances by a collegiate singer-songwriter — “This one is about my babysitter and how as you get older your relationships change” — and Rep. Rashida Tlaib of Michigan. Tlaib’s voice rose in emotional peaks and cracks as she spoke of her childhood in Detroit, which in her memory is perfumed with the rotten-egg smell of hydrogen sulfide. She bemoaned the building of “bougie” condos in her city. “We need somebody that’s courageous, that won’t sell us out,” she said. “I’m exhausted about the broken promises, these polished speeches — I don’t care if you said the same thing.” With Sanders, she said, “you see this person and he’s real.” It was as succinct an endorsement as a 2020 Democratic candidate could ask for; though, as we all well know by now, what’s “real” is ambiguous and mutable and very much according to one’s taste.

But of course, the crowd cheered; there was no higher praise.

Laura Bronner contributed analysis.

Make sure to check out FiveThirtyEight’s Democratic primary forecast in full; you can also see all the 2020 primary polls we’ve collected, including national polls, Iowa polls, New Hampshire polls, Nevada polls and South Carolina polls.