The muted boos came from a group of Bernie Sanders supporters in the back of the room, where more than 150 Georgetown University students had gathered on campus – standing room only – to watch last week's Democratic presidential debate. They were audible against the backdrop of relative silence as former Vice President Joe Biden made opening remarks, and they stood in sharp contrast to the spirited cheers, claps, whoop-whoops and snaps summoned for Sanders and Elizabeth Warren.

For those not following the early primary closely, the students' reaction to Biden, who frequents the Jesuit university to celebrate Catholic Mass on Sunday afternoons, was perhaps unexpected. For Rebecca Hollister, the chairwoman of Georgetown University College Democrats, the reaction was spot on.

"I don't know anyone personally who is supporting Biden," she says. "I don't think he gets a lot of people my age terribly excited."

"Don't get me wrong, he was great a vice president and I appreciate what he's done," the 19-year-old junior is quick to say. "But he's old. I'm just going to say it: He's old. I think it's time for something new and I think it would be hard for him to rally younger individuals."

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Hollister's assessment mirrors the narrative coming out of the polls, which uniformly show the 76-year-old Biden dominating the primary field with voters over the age of 50 – an important voting bloc that's historically been the most reliable for turning out at the polls – but floundering when it comes to engaging younger voters. One recent poll showed the former senator from Delaware garnering just 6% support among Democratic voters 18-49.

Biden's campaign has acknowledged that he has work to do to better appeal to the demographic, though his poll numbers don't seem to be setting off any alarms and there doesn't seem to be a sense or urgency to play catch up.

Other candidates have been mobilizing students for months , running Camp Kamala and Sanders Summer School, for example, or building out campus field offices established last spring before students left for the summer, as Warren and Pete Buttigieg did in early primary states like Iowa. In comparison, the Biden campaign launched Students for Biden only last month, marking his first major push to organize college students.

"Young people on college campuses are vital to this effort," Symone Sanders, senior adviser to Biden, said to students on the kick-off call for Students for Biden last week. "Y'all are vital to the primary process and vital to the general election."

The remarks from 29-year-old Sanders, who is widely credited with sparking the revolution for Sen. Bernie Sanders of Vermont among young people when she worked for his presidential campaign in 2016, was a surprise for the students who dialed in to the brief call, during which campaign staff outlined plans to help students mobilize their individual campuses.

"We are looking forward to working with you," Sanders said. "You all are going to be the ones who are really going to get this thing done."

She left them with this piece of advice: "Y'all are powerful. If you go to the ballot box, things will change. There is not a more powerful voting bloc."

This is true generally of voters younger than the baby boomers: Voters age 18 to 53, including Gen Z, millennials and Gen X, cast more votes than baby boomers and other older generations during the 2018 midterm election, according to the Pew Research Center , 62.2 million votes to 60.1 million votes. The turnout marked the second election in a row in which younger voters eclipsed older voters. The majority of Gen Z and young millennial voters, including the nearly 24 million students who are either expected to attend college in fall 2019 or expected to graduate from high school during the 2019-20 school year, tend to vote Democratic, and candidates have strategically tapped into their energy, influence and organizing power to propel their campaigns.

As it stands, the majority of young Democratic voters are flocking to Sanders and Warren early in the primary, and taking good looks at Buttigieg, mayor of South Bend, Indiana, and former Rep. Beto O'Rourke. Many Democratic strategists and pollsters say, however, that Biden's lackluster support likely won't be a problem because young voters turn out in low numbers for the primary, a process awash with voters over 50. If that holds true in 2020, they say, the vice president's nomination may be all but secured barring a major disqualifying gaffe.

But some of those same strategists warn that not making a good-faith effort to engage with young voters on issues they care about during the primary under the assumption that they will ultimately support whoever the Democratic nominee is creates enormous risk for the general election.

"This is the problem that the Clinton campaign had in 2008 and in 2016," John Della Volpe, director of polling at Harvard University Institute of Politics, says. "They basically used that theory, which is completely fair. We have limited time, limited resources, and younger people don't often vote in primaries. At the end of the day, they will come back to us."

"Ask President Hillary Clinton how that worked out," he says. "That is a dangerous, dangerous strategy."

One of the reasons young voters are famously elusive is because they vote differently than other demographic groups. They aren't party-ticket voters, they aren't impressed by electability, and candidates can't win their support by crafting specific policies on issues that matter to them. They respond instead to candidates they think share their values and vision for how the country should work and who it should work for, which is why young voters are gravitating to candidates like Sanders and Warren, who talk about the need for structural change and have outlined a clear plan for flipping the script.

"It seems like Biden has an assumption that's like, 'Oh I can win and get things back on track and then leave,'" says Hollister, a political science major. "That's not all we care about. We don't just want things to get back to normal. We want things to keep progressing. The youth doesn't just want a return to the status quo. That would be nice, but we want to aim higher than that."

But young Biden supporters are not unicorns. They exist and they exist all over the country, including in important primary states like South Carolina.

"I'm looking for a candidate who has experience and knows how to get the job done," says William Fairfax, a 21-year-old senior at Claflin University, a historically black college and university in Orangeburg, South Carolina, who is interning for the state's campaign office.

"I'm looking for someone who has years of experience in working alongside not just Democrats but Republicans as well," he says. "Because that's what it's going to take to get things done. It's going to take a lot of work to reverse the damage that the current occupant of the White House has done."

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Among other things, Fairfax says he's bolstered by Biden's commitment to overhauling the criminal justice system, a sweeping plan he unveiled this summer that would reduce the number of people incarcerated, reform policing and shift spending from incarceration to prevention through increased funding on social supports.

The campaign is laying the groundwork to attract more young voters like Fairfax. In Nevada, Students for Biden collected more than 1,000 commit-to-caucus cards on college campuses in the last two weeks alone. Biden's campaign has a paid youth outreach director in Iowa and is in the process of hiring five more full-time campus organizers focused on expanding Students for Biden across the state. And in South Carolina, a youth vote director is focusing on organizing Students for Biden groups with a particular focus on historically black colleges and universities.

If he made a more direct effort, strategists say, the factors are in place for Biden to generate support among young voters and, in many cases, his legislative record speaks to the very issues motivating them today, including gun safety and campus sexual assault. In 1994, Biden was key to pushing through Congress an assault weapons and magazine ban that was in place until it expired in 2004. Biden was the first member of Congress to introduce the Violence Against Women Act, which became law in 1994, and was the point person during the Obama administration to combat campus sexual assault.

That very long record and attachment to government, others say, is exactly what's getting him in trouble with young voters.

"If you look at any number of measures when we're talking about young people, there is a deep alientiaton in terms of how they think the government functions and who they think it functions for," says Cathy Cohen, political science professor at the University of Chicago and founder of GenForward, a project housed at the university that specializes in surveying and polling young voters 18 to 36 years old with a particular emphasis on communities of color.

"They're more likely to say that the government is run for big interests," she says. "They are more likely to rate favorability of Congress and the president as low. If part of your record is, 'I've been here for 40 years,' you've already got an uphill battle."

There's a significant caveat here, Cohen points out, and that is Biden's attachment to former President Barack Obama, an attachment Biden emphasizes every chance he gets (at least a dozen times in last week's debate, for example).

"Particularly for young African American people, that is meaningful," Cohen says.

For Fairfax, Biden having been vice president is everything, he says.

"He served as the vice president to the first African American president, and if Barack Obama trusted him then I know that I can trust him and a bunch of people in our school can trust him. And that goes a long way," Fairfax says.

Biden drove that point home at the debate last week when talking about health care: "She's for Bernie," he said of Warren, both of who've been nipping at his heels in the polls. "I'm for Barack."

Even still, Cohen warned, candidates can't take support for granted.

"It's a lesson from 2016, which is not to assume the base is going to turn out for you and in particular communities of color," Cohen says.

GenForward's polling shows that Biden has a 6% to 7% advantage among young African American voters compared to the rest of the pack, a margin much too close, Cohen says, to consider locked down.

Ultimately, she says, Biden has to talk about the issues that matter most to young people and direct his conversation to them.

"It's one thing to talk about climate change and it's another thing to talk about climate change to a generation of young people who will be faced with the consequences of climate change," Cohen says. "It's one thing to talk about the economy and it's another thing to talk to a generation who entered the workforce during the Great Recession. If we're not talking to them, then we are not talking to a critical political constituency both now and in the future."

Students at Georgetown will have an opportunity to hear from the candidates themselves about their plans to tackle climate change this week, when the university hosts a climate forum with MSNBC. So far, 11 Democratic candidates are confirmed. Not among them: Biden.

"Whenever I think about [the race], I have to remember that the people I interact with every day are really into politics," says Hollister, adding that students on campus have been more motivated and active in politics since the 2016 election. Membership in the Georgetown University College Democrats, for example, shot up 200%.