But contrarianism runs deep in the senator from Vermont—a 2016 campaign aide once described one of Sanders’s main animating principles to me as: “Fuck me? No, fuck you!” With his comeback, Sanders seems to be saying just that—not only to any detractors ready to write him off, but to the organ pumping inside his own chest.

And his supporters have responded.

“I kind of thought [his heart attack] was the end of the campaign, but the boost has been significant, and I’m encouraged by it,” said Quinn Miller, a 33-year-old city-government worker wearing a blue Unidos con Bernie T-shirt.

“It got everyone rallied,” said Erik Pye, a 45-year-old Army veteran and store owner from Brooklyn. “It gave everyone a sense of urgency.”

The incident seems to have made serious again all the Sanders supporters who’d recently wandered off, I observed to 28-year-old Elizabeth Johnson, who’d traveled from Rhode Island with her boyfriend. “Serious,” she joked, “as a heart attack.”

At the start of Sanders’s 2020 run, his aides made a point of telling reporters that his approach would be different from 2016: He would speak more personally about his life story and how his own experiences are at the root of his democratic-socialist politics—an attempt to connect with voters who kept their distance four years ago. That strategy lasted one weekend. At events since then, he’s often taken on the air of an annoyed grandfather who wants to say “I told you so” to the Democratic candidates who’ve adopted some of his more progressive policies.

Read: The return of Bernie Sanders is bigger than Bernie Sanders

The heart attack has given the campaign new material, and a new message. “Bernie’s too old?” asked the filmmaker Michael Moore, mocking pundits, in his endorsement speech at the rally. No, he said, what’s too old is the Electoral College, a $7.25 minimum wage, and the use of fossil fuels. People are worried about Sanders’s health? Moore said he’s worried about the health of the planet, and the health of young black men shot by police. “The only heart attack we should be talking about is the one Wall Street is going to have when Bernie Sanders is president of the United States,” Moore said.

In a nod to supporters’ suspicions about anti-Sanders sentiment in the Democratic Party, Nina Turner, the former Ohio state senator who is a campaign co-chair, told the crowd to beware of ageism, and noted that Sanders was the only candidate asked about his health at the Democrats’ latest debate. (Of course, he’s the only one who recently had a major health incident.)

Perhaps most important, Sanders’s heart attack seems to have encouraged Ocasio-Cortez’s attention-grabbing endorsement. They had breakfast in his hometown of Burlington, Vermont, a few days before the episode, but her announcement’s timing was motivated by her desire to give the campaign a boost right when Sanders needed one, her advisers have said. Now, Sanders said in his speech, they’ll travel the country together, aiming to create what she called “a mass mobilization of working people.”