AMES, Iowa — It’s 25 degrees in Ames, and students at Iowa State University are bundled up in parkas and puffer jackets, speed-walking past piles of snow on the way to classes and meetings near the school’s library. In the middle of all the confusion is Dhruv Raturi, a 26-year-old international graduate student who won’t be participating in Monday’s presidential caucus but who’s still trying to get other students on campus to commit to caucusing for Bernie Sanders.

“Bernie stickers! Hey! Do you want a Bernie sticker?! They’re rainbow-colored!”

“Hey, guys! Are you planning on voting in like, literally, less than a week?”

“Do you know about Bernie Sanders?” Raturi, an engineering student, politely yelled to people passing by while waving flyers with Sanders’ policies and instructions on how to get registered to caucus before Monday.

Young voters have always been a key part of the Sanders coalition. In 2016, Sanders won 84% of voters between the ages of 18 and 29 during the Iowa caucus, according to Iowa entrance polls, and he has focused on campaigning on college campuses in the state in the lead up to this year’s caucus. Last fall, Sanders hosted rallies at universities across Iowa during a grassroots tailgate tour, and on Saturday he hosted another rally near Iowa State University with Portugal the Man and Rep. Alexandria Ocasio-Cortez.

“The younger generation today is, in my view, the most progressive young generation in the history of this country, and for every three young people who vote, two out of those three will vote progressive,” Sanders told the crowd. “The not-so-good news is that same generation historically hasn’t voted in very large numbers. So tonight I’m saying to that generation is: If you are tired of student debt, if you are sick and tired and scared about climate change, if you are disgusted with racism, and sexism, homophobia, and xenophobia, and if you believe that health care is a human right, then you can’t sit it out and you can’t complain.”

Organizers at Iowa State are working to make sure those students actually show up to their precincts on Monday and have been canvassing students on campus since September.

“We’re building every day and bringing new people into this movement,” Stanley Njuguna, a campus organizer for the Sanders campaign, told BuzzFeed News. “We think students and young people have a lot at stake in this election even if they haven’t thought about that yet. These groups are his most important constituency in this election.”

“We have a few hundred ISU students who’ve already committed to caucusing for Bernie,” Njuguna added.

Thirty-five percent of Iowans between 18 and 29 years old say that they’re “extremely likely” to caucus on Feb. 3. Sanders leads all presidential candidates among young voters who’ve registered or identify as Democrats with 39% saying that they plan to caucus for him, according to a Circle-Tisch College and Suffolk University poll.

“I’ve been talking to a lot of undecideds! A looooooot of undecideds,” Njuguna said about students he’d canvassed over the past two weeks. “Usually we’re the first campaign that’s tried to engage them in what’s going on, and we’ve had a pretty good return on getting those people to commit to caucusing for Bernie.”

While dozens of students walked by the busy thruway on the way to class, some stopped to grab a sticker from Raturi and to tell him they’d already committed to caucus for Sanders. Other students told him that they still weren’t sure who they’d be caucusing for, and got to hear Raturi’s pitch.

“You’re an undecided voter? That’s great! You’re exactly who I’m freezing my ass off trying to talk to, because you’re going to determine the future for everyone,” Raturi told a student who’d wandered over to the spot he was canvassing. He handed the student a Sanders flyer and chatted about Medicare for All.

Sanders organizers and volunteers were primarily focused on identifying students who support the senator or were likely leaning toward supporting him and making sure that they actually turn up at the caucus, Njuguna said. But if they encounter supporters of Elizabeth Warren or Andrew Yang, Njuguna said that canvassers will still chat with them about good reasons to support Sanders.

On caucus night, candidates at most precincts need to gain support from at least 15% of the people who have shown up to be viable. When a candidate doesn’t reach the viability threshold, their supporters are free to join a viable candidate’s supporters, go home and not vote a second time, or join supporters of a candidate that’s close to the viability threshold during a realignment vote.

Sanders organizers said they are still reaching out to those voters they think may be interested in his platform just in case their preferred candidate doesn’t reach the viability threshold on caucus night.

“We know that, for example, Andrew Yang supporters — a lot of them come from the base of people who supported Bernie in 2016. I actually hear that a lot,” Njuguna explained. “So with people who are absolutely committed to Andrew Yang, it’s just like: OK! Fine, we’re all a part of the same base. So if Yang isn’t viable, are you gonna caucus for Bernie?"

“We think that’s important. We don’t want to lose those voters, and they’re still sort of down with Bernie’s platform.”

While canvassing at Iowa State, Raturi invited Sanders supporters and undecided voters who were leaning toward him to a pizza party on caucus night to make sure they’d printed off the correct documents and to make sure they get to the right precinct location on campus.

Raturi told two students he’d informed how to register to vote in Iowa that there are three main reasons people don’t caucus. “One, they forget the date. Second, they feel uncomfortable and they don’t go. Third, they don’t bring the right documents.”

“So it’s like, come! Let’s get some pizza on campus, and we’ll walk you over to the different precinct locations,” Raturi said. “Consider doing it! We all know that going together makes it more comfortable, and even if you feel comfortable on your own you can make it easier for someone that might have social anxiety so they can vote for Bernie, too!”

During the end of Raturi’s canvassing shift, a student, who had just opened her own restaurant, transferred to Iowa State University, and moved to Ames with her partner and child, passed by a group of Students for Sanders organizers and volunteers. She didn’t know about the caucusing process or when it would be happening.

“It’s like voting — with your body,” the organizers explained to her, handing her a flyer and telling her about Sanders’ stances on education reform and health care. They gave her information to help her find a babysitter so she could show up for the caucus.

She made plans to caucus on the spot. “Wow! You’re a badass,” they told her.

“A lot of students aren’t used to engaging in the political process and then Iowa makes it harder with this weird thing called a caucus, so we just wanted to let people know that they’re coming into a community that’s also passionate about the issues that they are,” Njuguna said. “The caucus seems intimidating, but it’s not! It’s just democracy in action. It’s voting with a little spice. A little razzle-dazzle! And when you put it that way, they’re more receptive to turning out.”