SIOUX CITY, Iowa — All across Iowa, as the Bernie Sanders campaign traversed the state east to west, from small towns to college campuses, there was a certainty. A certainty that, in the middle of most rallies, a harried staffer would dash across the stage at a crouch, bearing a stool.

That stool was the domain of Rep. Alexandria Ocasio-Cortez, who likes to grab the mic out of its stand and sit down, her arm casually rested against a lectern, as she tells personal stories and calmly articulates the case for a political revolution.

Images of her circulated online often seem to catch her mid-sentence and gesturing, a near-perfect caricature of an angry, scolding, far-left scourge of establishment Democrats. That impression has, at times, been earned — often to the delight of the right. But to the rapt crowds who populate the Bernie bubble in Iowa, she was all energy and empathy, talking about how Medicare-for-all and abolishing Immigration and Customs Enforcement were just a matter of common sense and human decency.

This past weekend, with the Iowa caucuses looming Feb. 3, Ocasio-Cortez was on a three-day, 10-event mad dash across the state. The senator from Vermont had asked her to be his voice while he was stuck in Washington, as she said, “fighting the good fight on impeachment.” (He got out of impeachment duty unexpectedly early Saturday and made it to Iowa by late afternoon.)

Wherever the campaign needed her, she showed up, racing across Iowa’s vast, snowy fields with barely an hour between shaking hands in one town and rousing the crowd in the next. At a canvass launch in Fort Dodge, a dying meatpacking town, so many people were crammed into an upstairs office space that there was barely room for a microphone. At a packed auditorium in the college town of Ames, an additional 400 to 500 people showed up and had to be stationed in a basketball gym.

In Sioux City in the far northwest, at a raucous rally of more than 1,200, she sat on that stool and talked about how her mother had cleaned houses when she was growing up in the Bronx and Westchester County, N.Y., and how “I would do my homework on other people’s kitchen tables, and I would read books on other people’s staircases. And even in high school, my mom cleaned an English teacher’s house for free so that I could have SAT lessons.” She talked about school counselors who discouraged her from applying to Boston University, where she eventually went, and about her first job, at 14 or 15, as a hostess at an Irish pub, where she first learned to pull a Guinness.

“I won’t say which one,” she said, laughing, “because they paid me under the table.”

Before that crowd at Sioux City’s convention hall, she wove together this story of being a kid in houses her family could never afford with Sanders’s background as the son of a paint salesman, and how they’d both wound up on Capitol Hill, “one of the ultimate places where working people aren’t supposed to be,” she said. Then she moved on to imploring the crowd to show up for Sanders at the caucuses and change the country.

And she did it all with that stool and without referencing notes, which her 2020 congressional campaign spokesman, Corbin Trent, says is the norm. “She used a teleprompter once,” says Trent, “and she was pretty good at it, too. She just doesn’t like using it.”

Gary Lipshutz, 77, a liberal who’s been active in Democratic politics since the ’60s, said he’s impressed.

“I mean, you could hear a pin drop in that room, and this is a girl from the Bronx in Sioux City, Iowa!” he said. “I’ve seen 19 presidential candidates this year. I think she had the most magnetism of any of them. Bernie included.” (Lipshutz is caucusing for Warren and came to the rally solely to see Ocasio-Cortez.)

Her big role in the campaign is being called a catalyst for Sanders’s recent surge in the polls. Her support for him runs deep: She was a self-described “scrub” knocking on doors as a Sanders field worker in 2016, well before she ran for Congress. And she was at his side in October, when his campaign had begun to decline after his heart attack, endorsing him (and calling him “Tio Bernie”) to a crowd of 25,000 under the Queensboro Bridge in New York City.

“I think everybody now, even in the small hindsight that we have, sees that as the moment that it turned around,” says the filmmaker Michael Moore, another Sanders loyalist who spoke at all of AOC’s events and is stumping for Sanders in Iowa for 12 days straight. Two of the other three members of the so-called Squad of freshman congresswomen of color, Ilhan Omar (D-Minn.) and Rashida Tlaib (D-Mich.), came out with their own endorsements around the same time. “I was there in Queens with a front-row seat,” says Moore, “and I just thought, ‘If she can do that for the next president of the United States, what other wonderful power does she hold in her hands? And what’s the good she’ll do with that?’ ”

The superstar surrogate

All the senators left in the race — Elizabeth Warren, Amy Klobuchar and a barely registering Michael F. Bennet — have the same dilemma as Sanders: being required to spend long hours, six days a week devoted to Trump’s impeachment trial. They need surrogates to keep their momentum going. In Iowa, Warren had Julián Castro, a former presidential candidate himself, and in New Hampshire, activist-actress Ashley Judd. Klobuchar’s Iowa surrogates included her daughter, Abigail, and curling champion and former Olympic coach Phill Drobnick.

But none of the others have been the kind of draw that Ocasio-Cortez has been.

“Look, I’ll say it, she’s the progressive movement’s rock star,” says Stacey Walker, the first African American to be elected as county supervisor in Iowa’s Linn County, which encompasses Cedar Rapids. “So when she comes through, for people in the political space, she’s our Beyoncé.”

At her first headlining event, minus Sanders, on Friday night at University of Iowa in Iowa City, several young bearded men waved a giant homemade sign with her initials and the ‘o’ replaced with a globe, while the crowd of hundreds chanted, “AOC! AOC! AOC!”

Sanders is a candidate who presents himself less as a personality than a conduit for a movement. And in the Bernie bubble, Ocasio-Cortez is seen as the future of the movement embodied. What makes her so effective as a surrogate, beyond her star power, is that if you campaign on electing a movement rather that a person, there’s no difference between hearing the message from the 78-year-old white male candidate or his 30-year-old Latina supporter. The perception among her supporters is that a vote for Sanders is also a vote for Ocasio-Cortez to continue her rise.

In fact, she’s been so focused on articulating her vision of the country, of “fighting for people we don’t know,” as she has said many times, that at that first event, she spoke for 20 minutes and never mentioned Sanders’s name.

Breathless headlines and articles speculated that the Iowa trip was a prelude for something bigger.

“AOC Is Campaigning for Bernie Sanders in Iowa and Voters Are Falling in Love,” wrote BuzzFeed News.

“Alexandria Ocasio-Cortez Wows in Iowa, Probably Not for the Last Time,” wrote New York Magazine.

“ ‘I really hope she is the future’: AOC’s support of Sanders fuels 2024 speculation,” wrote the Guardian.

2024 would be the first year that Ocasio-Cortez, who was the youngest woman ever elected to Congress, would be old enough to run for president.

Even her most enthusiastic fans, though, find that time frame a little over-the-top.

“Bernie’s another white male. It’ll be a nice ease for America, and then I think in 10 years they’ll be a lot kinder to AOC,” says Daneissa Folker, 24, who’s black and showed up to the morning Cedar Rapids canvass launch after a overnight shift at a hospital emergency room.

“Oh, she’s going to be the first Latina president of the United States,” said Kenia Calderon, 26, a Deferred Action for Childhood Arrivals recipient from El Salvador who saw her at a campaign office in Ankeny, outside of Des Moines. “But she has a lot more work to do in Congress.”

“I predict when she’s 45, or longer,” said Calderon’s sister Fatima, also a DACA recipient. “We’ve got to get Bernie elected first.”

Despite the glow, a rocky year

Sanders is consistent about many things, including the line he used to thank Ocasio-Cortez at the seven of 10 Iowa campaign events he showed up at and the two he phoned into last week.

“I have been in Congress for a few years” — pause for laughs — “and I honestly cannot recall any single first-term member of Congress having as much impact on our country as Alexandria has.”

Impact, yes, but it’s been a rocky year.

She’s been a political superstar since her upset primary win in 2018, as the bartender who handily beat a 10-term incumbent who was also the fourth-most-powerful Democrat in Congress.

She ran as a democratic socialist, meaning she hoped to create a benevolent state safety net like that in Finland, but was painted by her political opponents as someone who wanted to turn America into Cuba.

Her Twitter following coming to Capitol Hill was so big (then 3.8 million, now 6.2 million) that her congressional colleagues asked her to give them lessons. Her family is of Puerto Rican descent, and she drew the ire of President Trump, who told her and other members of the Squad to “go back and help fix the totally broken and crime infested places from which they came,” even though all are U.S. citizens and all but one of them was born in the United States. (Ocasio-Cortez, like Trump, was born in New York City.)

She drew the ire of Fox News and Fox Business, which studies showed mentioned her an average of 75 times a day for six weeks and mocked her shoes, designer clothes she wore for a photo shoot and a video of her dancing in college — one that was meant to embarrass her as carrying out conduct unbefitting a member of Congress, but only served to further endear her to supporters. She drew the ire of House Speaker Nancy Pelosi for joining in a climate-change protest outside Pelosi’s office at the start of the term and for being the one Democrat who voted against reopening the government after the 2019 shutdown, because the bill continued to fund ICE. She got flak from both sides for introducing her first piece of legislation, the Green New Deal, with a flawed summary. Senate Republicans easily defeated it. Pelosi called it “the green dream, or whatever.”

At the same time, she’s earned the praise of conservative commentator David Brooks for her thorough, tough questioning of witnesses in congressional hearings, with videos of her floor speeches and her grilling of Facebook CEO Mark Zuckerberg and a former ExxonMobil consultant going viral.

“She’s made me feel like I can inspire other people. I’ve shown a lot of people her videos,” said Travis Terrell, 34, who had come to the Cedar Rapids event with Folker after their emergency room night shift. “I would vote for her tomorrow,” he said. “I think I’ve donated more money to her than any candidate in Iowa.”

At the canvass launch the next day in Ankeny, Esperanza Pintor Martinez, a Mexican immigrant, had waited for over an hour with her 3-year-old daughter, Zarai, to hear Ocasio-Cortez. “It’s important for me as a Latina to bring my daughter here and show her that we can show up and do something, in this country where Trump is trying to extinguish us and make us go away,” she said.

If there was dissent outside that bubble in Iowa, though, Ocasio-Cortez didn’t see it. She traveled with an all-female of her campaign manager, a field officer and a photographer. The media was kept at a distance, and she was not available for questions.

As Ocasio-Cortez campaigned her way through Iowa for Sanders, she turned the ups and downs of her first year in Washington into strengths.

At a solo town hall in Cedar Falls at the University of Northern Iowa, she told the story of how she got to Congress and realized she wouldn’t get her first paycheck for an entire month, yet was being attacked by Republicans for being unable to pay for maintaining apartments in both her New York City district and Washington.

“It’s funny because there’s a lot of kind of confusion in messaging, especially from the right,” she said. “One minute I’m a know-nothing. The next minute I’m a mastermind who’s taking over the party. They can’t figure out if I’m an elitist or if I’m embarrassingly poor — which there’s no such thing.”

She couldn’t afford “a second home,” and she certainly couldn’t afford a second set of furniture, she said, so for her first three months in Congress, she slept on an air mattress. “And it was such a surreal experience, because I’d wake up on that air mattress and I’d walk to my work where the nation’s laws are made and be told all the time that health care for my family wasn’t possible. . . . To be able to walk into a space and be told that our lives are too politically inconvenient to fight for is quite an experience.”

Soon after, a woman stood up, sobbing, and told the story of how her wages were being garnished to pay off her medical debt. Ocasio-Cortez gave her a hug, told her that a system that asked that of her was “morally wrong” and launched into another story. Eighteen months ago, when she had only catastrophic health insurance with an $8,000 deductible, she said, she’d tried to pay a doctor with a bag of her cash tips, then burst into tears when the doctor told her she needed a blood test, because she couldn’t afford one.

“And the doctor said, ‘What do you do for a living?’ And I said, ‘I’m running for Congress.’ ”

At that same town hall, an Asian immigrant from Brooklyn stood up and began telling a long and winding story of his awakening to the idea that society saw him as different, and how his time in the military had shown him that people all around the world aren’t so different from one another; they just want dignity, freedom, home, “and if you’re lucky you get to spend that journey with loved ones.”

There was no question in sight, and that had been clear from the beginning, but when the man apologized for taking so long, Ocasio-Cortez laughed and said, “You’re halfway there. Keep going!”

Filmmaker Moore said someone took a picture of him weeping during that moment.

“That guy, he went on and on, and at first it was a little weird, but she sat down on the stool,” he said. “She didn’t have that look of, ‘Hurry up,’ or, ‘Let me interrupt you.’ She let him tell his whole story, and when the story expanded and we all heard it, the people were choked up in the audience. A normal politician would not have let a guy go on that long. That’s what’s different about her. She’s not thinking like a politician. She’s thinking like a human being. She’s not that far from that bag of cash and the air mattress.”

As the crowd filed out of the town hall, the stool remained onstage. At the last stop of her tour, though, the staff finally remembered to hide it inside the lectern so Ocasio-Cortez could take it out whenever she was ready.