When Jarae Hines arrived in Des Moines last March to work as a field organizer for Elizabeth Warren’s presidential campaign, he had no intention of living with a total stranger like Ale Gomez.

“I said, ‘We’re gonna live together,’ and he said, ‘Absolutely not, I have no idea who you are,'” recalls Gomez, sitting in Warren’s Beaverdale, Iowa field office. Two weeks later, the young staffers were roommates, living in an industrial apartment with a concrete floor, no decorations and a foster cat with a skin condition, even though Hines is allergic. “She organized herself into having a roommate,” Hines says of his persuasive friend. “And she organized herself into having a cat.”

Warren’s field office in Beaverdale sits in a strip mall next to a podiatrist’s office. It’s papered with messages to reinforce the campaign’s friendly-fighter ethos. One wall features notes from supporters; another displays folders detailing Warren’s policies, under construction-paper cutout letters spelling “she has a plan for that.” A trio of hand-drawn signs labeled “Outwork,” “Out-organize,” and “Outlast” include instructions to “be the ultimate Warren stan” and “be the nice campaign.”

If Warren wins Iowa, it will be due in large part to the people who work in places like this. Hines and Gomez are part of the vast army of field organizers and volunteers that has made the Massachusetts Senator’s campaign the best-organized in Iowa, according to local Democrats. Even rival campaigns begrudgingly admit that Warren’s operation is formidable.

Jarae Hines at Warren's Ingersoll office; Ale Gomez at Warren's Beaverdale office Devin Yalkin for TIME

“Elizabeth Warren has the best ground game in the state right now. She’s been building that up for a year,” says Sean Bagniewski, chair of the Democratic Party in Polk County, who hasn’t endorsed a presidential candidate. “She has the most staff who are the most ingrained in the most Democratic communities in Iowa.”

All campaigns are knocking on doors, all campaigns are raising money, and all campaigns are trying to get voters to commit to caucus. But none have been doing it as long or as hard as Warren’s has in Iowa. She has been campaigning in Iowa for nearly a year, with roughly 150 staffers on the ground and 26 field offices. And it’s not just about numbers. Observers say that Warren’s campaign has been notable for the depth of its engagement in local communities.

When a local animal shelter needed a boost, Gomez brought Warren volunteers to help. When a neighborhood in Des Moines needed help with their community garden, Hines organized Warren volunteers to pull weeds and till the soil. “I said, ‘Great, we’ll be there every Saturday,'” he recalls. “We fed folks in the community where there are no grocery stores around. We went door-to-door handing out vegetables to people.” Hines says the area near the garden now has several Warren signs that weren’t there before.

As field organizers in Polk County—the most populous in Iowa—Hines and Gomez spend their days training precinct captains, calling volunteers and directing canvassers. But they’re also performing the crucial emotional labor that keeps the campaign running: making sure Warren supporters stay excited about their candidate. That work has taken on added importance in the final days before the Feb. 3 caucuses. With the candidate stuck in Washington for President Trump’s impeachment trial, it’s up to staffers like Hines, a 30-year-old from Nevada, and Gomez, a 23-year-old from Pennsylvania, to keep the Senator viable in the state.

Elizabeth Warren’s Beaverdale office in Des Moines, IA. Devin Yalkin for TIME

“I definitely think it has turned up the pressure,” Hines says of Warren’s unavoidable absence. “We have to be on our ‘A’ game, and we have to be talking about Elizabeth all the time.”

Hines and Gomez say they tell their volunteers never to bash Warren’s opponents when they encounter a supporter of a different candidate. “We say, ‘That’s fine, I like them too, what do you like about them?” says Hines. “We never speak negatively about another candidate.” That’s especially important in Iowa, where the caucus process allows supporters of less popular candidates to switch to another as the caucus goes on if their first choice flops.

“We know that we’re a lot of people’s second choice, and we know that if we start playing divisive politics that’s not going to help us,” Gomez says. “No matter who you’re caucusing for, we’re always going to be polite, respectful, kind. We know that’s going to win us delegates on caucus night for sure.”

It may help in long run, too. In a competitive primary with an outside shot at producing a contested convention, being the second choice for supporters of other candidates could be key in a drawn-out fight for the nomination.

The organizers’ dedication is rooted in their personal experiences. Gomez is a DACA recipient who identifies as queer. “There’s a lot at stake for me in this election,” she says. “The reason my life is used as leverage is because of corruption in politics.”

Ale Gomez works at the Warren Beaverdale office. Devin Yalkin for TIME

Hines’s mother was a mortgage broker before the financial crisis; when the economy crashed in 2008, she lost her job, her health insurance, and their family home. “That was a big moment in my life, when I really realized how fragile things are,” Hines recalls. The work Warren did to establish the Consumer Financial Protection Bureau, which regulates financial lenders, earned her Hines’s support. Working in real estate before he joined the campaign, “I saw the actual regulations being put in place that made lending a lot clearer for folks,” he says.

They’re hardly the only ones pounding the pavement for Warren. Hines and Gomez named their orange tabby foster cat Carl, after Carl Schumann, an octogenarian Warren volunteer who is one of the campaign’s most dogged local canvassers. Schumann started off knocking doors twice a week, Gomez says, then graduated to four times a week.

“I’m very impressed with his dedication,” says Gomez. “He thinks it’s the last campaign he’ll be able to knock doors for, and what better way to end his canvassing experiences than by trying to elect the first woman president.” As Gomez and Hines they were telling this reporter about Carl the cat, another organizer knocked on the door to tell them that Carl the human had arrived at the office for his canvassing shift.

In January, Carl the cat was passed off to a local family looking to adopt. As soon as she met them, Gomez knew it would be a good fit: Carl has a skin condition that results in scabs and sores, and the family had said wanted to adopt a cat with special needs. “Then, I found out they were caucusing for Warren,” she says. “I got their contact info.”

Now that she thinks about it, she says, “I should check in with them.”

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Write to Charlotte Alter at charlotte.alter@time.com.