“Sanders’ standing has only increased since he had that incident,” said Jeff Link, a longtime Iowa Democratic strategist. “It was a wake-up call for people who were totally committed to Bernie, like: ‘We got to make this time count.”

Three events last week in the first-in-the-nation caucus state illustrated his comeback: With Ocasio-Cortez campaigning alongside alongside him, his campaign pulled in larger crowds at each stop than it had at any others in Iowa this year. His first rally after his heart attack, which was held in New York City with Ocasio-Cortez, likewise attracted about 26,000 people, according to his team, which would make it the biggest event of any Democratic presidential candidate this year…

“AOC referred to it as a gut-check moment for her,” said Faiz Shakir, Sanders’ campaign manager. “I wouldn’t dispute the notion that it caused some people to envision a race without him.”

Ocasio-Cortez’s endorsement, in turn, appears to have influenced some Democratic officials: “I’d be remiss if I didn’t say it was inspiring to see someone like AOC and Ilhan Omar and others stand up to be counted,” said Linn County Board of Supervisors chairman Stacey Walker, who is now Sanders’ Iowa campaign co-chair after announcing his support in late October. “Yes, it weighs on me and it influences me.”