Gillum managed to get a meeting with Steyer, too. “At the beginning, he told me he had a rule around trying to stay out of primaries,” Gillum told me. “As I talked to him about what I believed, I told him, straight up, ‘In your brand of politics, you are never going to have anyone come out of these primaries who shares that belief system if you don’t get involved.’ ” He needed money to beat money. On June 28th, Steyer’s organization, NextGen America, announced it would commit a million dollars to support Gillum’s campaign.

But Gillum had also recognized that the big money in the Democratic Party—Steyer’s money, George Soros’s money—is now on the left, not the center. Last year, Gillum watched closely as Soros’s cash helped propel progressive candidates to victory in several local elections, including the Philadelphia District Attorney’s race. Gillum was familiar with Soros and his organization, the Open Society Foundation: a few years ago, he helped launch a national network for young progressive elected officials, and the Open Society Foundation was the group’s main donor. He had been in the financier’s New York apartment, addressed his board of directors, and, this spring, dined with him in San Francisco when the two men happened to be in town. Soros committed to back Gillum’s gubernatorial campaign. “If I’m remembering it correctly, it was, ‘We don’t know if you can win, but we would like what it could represent,’ ” Gillum said. “I interpreted it to mean that it would be significant to see a person of color taken seriously in a statewide race.”

The matter of how a poor young person might make it in a society arranged for the wealthy is one of Gillum’s main themes. At campaign events, he often introduced himself by saying he was “the only non-millionaire in the race.” At the outset, his campaign “couldn’t compete,” Gillum told me. “Look, what I’m facing here in Florida is decades of muscle memory around what our nominee is supposed to look like, sound like, where they are supposed to come from—I’m none of those things—even from progressives who may like me,” he said. “They also have muscle memory.”

It was the conservatives, Gillum said, who had rejected the Obamacare Medicaid expansion that would have insured seven hundred thousand Floridians, and conservatives who had kept ex-felons, his brother among them, from voting. In Tallahassee, he had opened up most municipal jobs to those who had been in prison, and found that they were among the city’s hardest-working employees. “We can have that kind of state,” Gillum said. The congregation prayed over him, right arms extended.

Last Sunday, Gillum spoke at St. Ruth Missionary Baptist Church, in Dania Beach, Florida. I was in a pew near the back. Over six feet tall, with a shaved head and handsome, Gillum took the pulpit and told the congregation about his life. He was born poor, in Miami. His mother was a school-bus driver and his father was a construction laborer. He was the fifth of seven children, and the first to graduate from high school. While finishing college at Florida A. & M., he became the youngest city commissioner in the history of Tallahassee, and then, when he was thirty-five, he became its mayor. Gillum portrayed his own rise as proof that Florida had once been a more progressive place, and that the recent conservative regime has been a deviation. “We’ve got to reinfuse into our public education what used to exist there,” he said.

Yet in the past few weeks there has been a change. The local newspapers have been acknowledging that Gillum is “ consistently the Democrat who can fire up crowds ” as the Tampa Bay Times put it last week. Senator Bernie Sanders visited Orlando and Tampa last Friday to endorse Gillum and rally for him. In the public polls, Gillum has pulled close to Graham and Levine, in what is now clearly a three-way race, and in the private polls that have circulated among political operatives, samizdat-style, he is said to be closer still. Watching it from afar, I thought that Gillum’s campaign seemed a test, in inhospitable climes, of how far the progressive revolution might go. Could a new-model Democrat win in an old and conservative state like Florida?

This wasn’t a name I’d expected. Gillum—the thirty-nine-year-old, outspokenly progressive, African-American mayor of Tallahassee, Florida—is running for governor this year, in a state that has been run by Republicans for nearly twenty years, and where Democrats usually nominate moderates. Gillum’s campaign platform calls for a steep corporate-tax increase to pay for a billion-dollar boost in public-education spending, a repeal of Florida’s Stand Your Ground law, Medicare for all, and a fifteen-dollar-an-hour minimum wage. The conventional wisdom, when Steyer and I spoke, was that Gillum’s chances in the Democratic primary were slim—the establishment favorite in the race was Gwen Graham, a former congresswoman whose father, Bob Graham, represented Florida in the U.S. Senate for eighteen years, and whose campaign emphasized environmental protection and the need for a more incremental approach to education and health care. Gillum was running third, fourth, or fifth in most primary polls, far behind Graham and the former mayor of Miami Beach, Philip Levine, a millionaire who was spending heavily on his own campaign, and who billed himself as a “radical centrist” and a problem solver. Gillum’s campaign, by contrast, was broke (his campaign aired its first television commercials only a few weeks before Tuesday’s primary), and was often mentioned in conjunction with an F.B.I. investigation into corruption in Tallahassee, which had orbited Gillum without directly implicating him.

A few weeks ago, I met the liberal billionaire Tom Steyer at the W Boston hotel. Steyer has been playing a unique role in the midterm elections . He has been on a personal tour of the country, headlining rallies at which he lays out the case for impeaching Donald Trump (events at which he is regularly urged, from the crowd, to run for President). He has also pledged to spend thirty million dollars to help elect progressives, a sum that makes him the most significant Democratic donor in America. A San Francisco financier with a blue-blood Manhattan pedigree (Buckley, Exeter, Yale), Steyer has the tycoon’s habit of smiling broadly after he finishes speaking. As we spoke, Steyer kept returning to a point he makes often in public: that the Democratic Party is undergoing a profound generational change, and that he wanted to use his influence to help spur it along. I asked Steyer which politicians he believed represented this change, and he said, “Andrew Gillum.”

Gillum planned to spend the last week of his campaign on a bus tour of the state, beginning with a kickoff rally on Monday, at Kleman Plaza, in Tallahassee, just across from City Hall. The form of the event was familiar enough (a benediction, enthusiastic speeches, carefully plotted campaign signs, insufficient shade), but the content was a little unusual. Gillum’s wife, R. Jai, once an ally of his in Florida A. & M.’s student government, said from the podium that when the mayor had proposed, he had asked her to be his “life partner,” rather than his wife. Eleven ministers surrounded the Gillums and prayed for protection and success over them, clerical right hands placed on the Gillums’ bodies. “The son of second-class citizens,” one minister intoned. The usual program of patriotic songs was elided. In its place the crowd, racially diverse, sang all three verses of the unofficial black national anthem, “Lift Every Voice and Sing.”

Photograph by Scott McIntyre for The New Yorker

There’s a subtle generational seam running through the rising class of Democratic politicians. Those born in the late nineteen-sixties, such as Kirsten Gillibrand and Cory Booker, came up taking their cues from baby boomers and are now working to repurpose their politics to meet a more ideological party. Those born in the nineteen-seventies—Chris Murphy, Stacey Abrams, Kyrsten Sinema, Beto O’Rourke—have spent their careers closely watching the millennials, and explaining their evolving politics to the Party’s elders. Gillum, who was born in 1979, has been an especially keen observer. Gillum supported Hillary Clinton during the 2016 Presidential campaign—he spoke at the Democratic National Convention, and appeared on a long list of thirty-nine potential Vice-Presidential picks—and her campaign sent him to a historically black school in Columbia, South Carolina, before the primary there, on Clinton’s behalf. “Hillary and Bernie had events on the same day,” he recalled. He walked through campus, encountering black frat brothers and trying to entice them to the Clinton event. “They were, like, ‘Nah, we going to see Bernie.’ ” Looking back, Gillum said, he tended to think that the Sanders movement had not really been about its specific policy proposals—the students in South Carolina hadn’t been seeking out Bernie just because of free college tuition. “I’m not even certain that all of them believed it was possible.” Gillum said. “This generation—they’re not single-issue. They weren’t there for free college tuition. They wanted real change. Real reform. Something big.”

His own view was that the Black Lives Matter movement had radicalized millennial politics—not its orientation so much as the scale of its expectations. “People feel free,” he said. “I remember hearing Issa Rae”—the creator and star of HBO’s “Insecure”—“say, ‘I’m rooting for everybody black.’ And my reaction—I thought, They’re going to sabotage her. I thought, There are going to be some consequences. And then—people are making shirts with that slogan. White kids are memeing it. It’s inspiring in some way because, increasingly, people are feeling that this shift is happening. There’s an impatience to it that’s going to be hard when I’m governor.” This dynamic, he believes, is part of what President Barack Obama had been up against. “Problem is, he is so brilliant that he negotiated himself into the pragmatic very quickly, because he wanted something done,” he said.

Gillum had paid special attention to the 2017 Senate special election in Alabama, in which the Democrat Doug Jones had upset the Republican Roy Moore on the strength of his support from African-American women—an older bloc of voters than millennials, but radicalized, too. To think about the black vote through women first, he said, opened up progressive possibilities. “I think you can certainly hedge a lot less when you are talking with black women about issues that have traditionally been a cipher in the black community—L.G.B.T. issues, the environment,” he said. The image of the Florida environmental movement was of the Graham voter—white, older, Birkenstocks-wearing—but he’d been campaigning in black communities against the corporate pollution that had left Florida with red tide and “guacamole-thick” algae. He said, “Women know that when the season shifts and the air changes you get asthmatic babies.”

Photograph by Scott McIntyre for The New Yorker

It was Monday evening, about dinnertime, and we were speeding in Gillum’s campaign bus across the Florida Panhandle, west toward Pensacola, a pretty little city on the other side of the pristine basin of Escambia Bay. It rained intermittently that day, and Gillum gave his stump speech to three dozen voters under a tent pitched in the parking lot of a Roses Express. As I heard the speech again—I would hear it several more times—I realized that in it he never mentioned Sanders, whose endorsement his campaign’s prospects had hinged on, and only sometimes mentioned Trump, even though his campaign commercials called for the abolishment of Immigration and Customs Enforcement and the impeachment of the President. His reference points instead were the cumulative political experience of the past few years—the police killings of young black men, the evidence of global warming, the mass teacher strikes, Parkland. What he meant to signal to his audience was that the dam was about to break.

“I honestly thought Sandy Hook was it,” Gillum told me at one point. “And Sandy Hook may have been it for Connecticut, but it was not for the rest of the country. We watched those bodies carried out of the school, we watched that precious loss of life, and it was, like, we’re not making changes here.” He took a sip from a soda can. “And at Pulse night club, forty-nine lives lost?” I asked Gillum why he thought the Pulse massacre had not had the same effect as the Parkland killing, in Florida, or in the country at large. He said, “Well, at Pulse, they were all gay.” He paused for a moment. “I don’t mean to speak cavalier about it,” he said. “But the governor couldn’t even wear a Pulse ribbon. Parkland was different because it was middle class, Americana. White children, by and large, from middle-class families. A city that had just been rated the safest in Florida. Just the juxtaposition of that.”

Further Reading New Yorker writers on the 2018 midterm elections.

Every progressive politician has a theory about Parkland. Gillum’s was that it allowed Americans to see clearly how “special and overprotected” a category legislators had carved out for gun owners. As the mayor of Tallahassee, Gillum had been sued by the National Rifle Association, in his official capacity and personally, over an ordinance that prohibited anyone from firing weapons in the city’s parks. One of the issues in the ensuing court battles was the legitimacy of a state law that allows public officials to be sued as individuals if they enact rules limiting the use of guns. “It’s the only such privilege that exists, and it relates to guns,” Gillum said. The Stand Your Ground law was similar, Gillum said. The law just backed away. He mentioned the death of Markeis McGlockton, a young black man who, in July, was shot and killed by a white man, in a dispute over a handicap-parking spot. “The standard is, you have to perceive a threat,” Gillum said. “Who is the arbiter of that? There is no black and white. There is only opaque, gray.”

It was getting late. We’d been talking on his campaign bus for nearly two hours, and an aide was trying to get Gillum to make calls to donors, but he brushed them away. “Aquilah has some West Coast donors for me to call,” he said eventually, a little regretfully, and a few minutes later he moved to the room at the rear of the bus—there was a divider midway through—and picked up his laptop and his phone. I chatted up the driver, who claimed to have driven both Trump and Hillary, though he was a little squirrelly on the details. Now and then the door to the back room opened and I glimpsed Gillum on his phone, always listening, never talking. I thought I could understand something about why it had been possible for Charles and David Koch, the billionaire industrialists, to reorient the Republican Party around their libertarian aims and views, and why it might be possible for progressive billionaires to do something similar. The dream was that one meeting with Tom Steyer might get you a million dollars and spare you a hundred conversations with orthodontists, who each had a few thousand to give.

There has been a lot of talk among Democrats this year about new coalitions and new voters. As Gillum moved through northern Florida on Tuesday morning (three events in Pensacola, then one in Panama City, and then, in the evening, on to Jacksonville), the voters who came out to see him were Democratic Party stalwarts—teachers, leaders of the black and queer communities, the stray local civil-rights icon in a fez, live-streaming proceedings. Gillum’s campaign did not depend on a plan to transform the Democratic Party so much as a conviction that he could recognize what had changed within it. On Thursday, Politico reported that Gillum had taken in a last-minute windfall of six hundred and fifty thousand dollars—three hundred thousand from Steyer, two hundred and fifty thousand from Soros, and a hundred thousand from anonymous individuals “affiliated” with those two billionaires. Gillum had an idea of where the electorate was headed, but the primary required that they get there on a very particular schedule, by 7 P.M. this coming Tuesday. On the stump, Gillum mentioned that if he won the primary he would be “the first candidate of color ever to lead a major party in the state of Florida.” He said, too, that Florida should be governed again by “everyday people.” I remembered Gillum sitting in the back of the campaign bus, phone pressed to his ear, a donor talking on the other end.