When Vermont Sen. Bernie Sanders suffered a heart attack in early October, it looked as if it might be the beginning of the end of an unsuccessful campaign for president. Through the summer, Sanders routinely polled in the top tier of candidates, but his support seemed fairly static, and observers wondered whether it reflected little more than lingering name recognition from the hard-fought 2016 primary against Hillary Clinton.
The dynamics this time around seemed to be different, and they also seemed to be shifting gradually, but perceptibly, in the direction of the other well-known liberal in the race, Sen. Elizabeth Warren (D-Mass.). Pundits wondered whether Sanders would quietly fade away.
What a difference a few weeks can make in a campaign.
In a fascinating political paradox, Sanders has been on a roll since his heart attack. His performance at the first, post-stent debate was robust, and his answers to questions about raising taxes to fund Medicare for All were commended by analysts as being more forthright than Warren’s. While Warren appeared to be cautious when pressed for details by the debate moderators and other candidates, Sanders was confidently unapologetic when making the case for his signature policy goal.
Today, Sanders seems refocused and reenergized at a pivotal moment on the calendar—and in contrast to some other candidates, who seem to be drifting. And many of the advantages he’s enjoyed all along—name recognition being only one of them—suddenly seem extremely pertinent to the state of the race.
First and most important, Sanders is flush with cash, having brought in $25.3 million in contributions during the third quarter, thanks to his extensive network of small donors who, if history is a guide, will be willing and able to make more donations as the campaign progresses.
Sanders’ fundraising prowess stands in stark contrast to other top tier contenders like former vice president Joe Biden, who has struggled to raise money equal to his status as the presumptive frontrunner, and Sen. Kamala Harris (D-Calif.), who this week cut staff in an effort to shore up her campaign’s finances.
Sanders is now putting the money to work. Following a massive rally in Queens, N.Y., where Sanders declared “I am back!” to 25,000 cheering supporters, his campaign announced that it was doubling the candidate’s schedule of appearances, adding a number of high-profile visits to must-win states like Iowa, Michigan, and Minnesota.
Along the way, Sanders has collected a series of endorsements from freshmen representatives including Alexandra Ocasio-Cortez (D-N.Y.), Ilahn Omar (D-Minn.), and Rashida Tlaib (D-Mich.), which bolsters his activist bona fides but even more crucially indicates that a meaningful chunk of the liberal grassroots—the younger chunk—is firmly behind him. Moreover, the fact that these high-profile women are supporting Sanders helps to ameliorate the negative Bernie Bro vibe that hung over his last campaign.
“Now that I am on the other side in the halls of Congress, it astounds me that he has been able to withstand the intense amount of pressure there is here to conform, to stay quiet, and to compromise the lives of working people so that we can accommodate the corporations and not the other way around,” Ocasio-Cortez said in a video she taped for the campaign and shared with her 5.7 million Twitter followers.
Sanders also has been a fixture in the airwaves, taping an appearance on Desus & Mero on Showtime and sitting for a lengthy interview with John Harwood on CNBC, where he encouraged the network’s deal-sled-wearing viewers to not be “overly nervous” about his brand of democratic socialism.
“What I am trying to do, in many ways, is pick up where Franklin Delano Roosevelt left off,” Sanders told Harwood. “The question is, is our economy working for the people here? Is it working for ordinary Americans? Do people feel secure? Do they know that when they get sick, they can go to a doctor in a hospital? Do they know that their kids, everything being equal, can have a better standard of living?”
There’s some evidence to suggest this message is standing out from the din of the day-to-day race. A recent Granite Survey poll conducted by CNN and the University of New Hampshire found that Sanders was the preferred candidate of 21% of respondents, ahead of Warren, who polled at 18%, and former vice president Joe Biden, who came in at 15%.
Dr. Andrew E. Smith, a professor of political science at UNH and director of the survey center, cautions that the statistical margin for error in the poll is large enough to mean that all three of the top candidates are effectively neck and neck. Still, Biden’s standing has slipped definitively since July in this survey of Democratic primary voters, and respondents—again, these are Democrats—had a relatively high unfavorable impression of the former vice president, at 33%. In contrast, Sanders was viewed favorably by two thirds of respondents, the highest favorability rating of any of the candidates, and his unfavorability number was only 23%.
“That to me is a problem for Biden,” Smith says. “He is supposed to be a guy who unifies the party, but when you look at unfavorability ratings in New Hampshire, the only two people with higher numbers are Marianne Williamson and Beto O’Rourke.”
In contrast, Smith notes that Sanders has broader ideological support than one might expect. In a race that has been described as a split among candidates on the left—Sanders, Warren—and those who are now positioning themselves as sensible centrists—Biden, Pete Buttigieg, and Sen. Amy Klobuchar (D-Minn.)—Sanders is more appealing to more types of Democrats, at least in New Hampshire, than many of his rivals.
“He’s been pigeon-holed as a favorite of the left, but in our survey he gets 16% support among liberals, 17% among moderate Democrats, and 17% among conservative Democrats,” Smith explains. “His support, interestingly, is fairly consistent across the board, and that’s something people have underestimated about him.”
Sanders’ strong results in New Hampshire come with plenty of caveats, of course. Smith notes that most voters have yet to pay attention to the campaign, and will make up their minds in the final weeks before the February 11 primary. He also observes that Sanders enjoys the most support (34%) among young voters, and struggles with older voters (garnering only 9% among voters age 65 or older), whereas Biden is popular with senior citizens (he is preferred by 25%) but lags among the young (only 6% say they support him in the primary). This could be a challenge for Sanders, as younger voters have historically been less likely to turn out, while older people are more reliable voters.
Still, the denouement of the pre-campaign campaign is upon us, meaning that the most committed Democratic primary voters are deciding who they want to support, and Sanders is showing renewed signs of strength.
Though he’s the oldest candidate in the field, he brings an energy and a clarity of purpose to his campaign that Biden so far appears to lack.
Though he shares many of Warren’s liberal values, he does not seem to be the lightning rod that she is among moderate, business-oriented voters (sexism is a factor, of course.)
He is much better known than candidates like Harris, Buttigieg, and Sen. Cory Booker (D-N.J).
And though plenty of Hillary Clinton supporters still distrust Sanders, they distrust Donald Trump more.
Beyond the persuadable voters, Sanders has always had one big thing going for him, and that’s the veritable army of true believers who have always had faith in him—the thousands of supporters who have written those small checks fueling that $25 million war chest that ensures he’ll be able to stay in the race for as long as he wants to. In the same way that Trump relies on a core group of supporters to power his campaign, so does Sanders.
In an op-ed published in the Minneapolis Star Tribune this week under the headline “After the heart attack: Why I still stand with Bernie,” a woman named Crystal Yakaki articulated the feelings of many longtime Sanders’ supporters in standing by their candidate.
“Let’s be honest: When I first heard about the heart attack that Sanders had early this month, I cried doing the dishes,” she writes.
But then when she considers the Trump presidency and the existential threat of climate change, Yakaki says, she is ever more determined to fight for an activist, progressive agenda.
“And that is where Bernie Sanders, stents and all, emerges as our greatest, unequaled contender,” she concludes.
More must-read stories from Fortune:
—Paul Ryan’s new foundation makes poverty experts and Medicare advocates nervous
—Voters over 65 remember Nixon—and want to impeach Trump
—How Mitch McConnell could use impeachment to scramble the Democratic primary
—Sherrod Brown has some advice for 2020 candidates hoping to win in Ohio
—Kids brought guns to school at least 392 times last year. What experts say we should do
Get up to speed on your morning commute with Fortune’s CEO Daily newsletter.