WALPOLE, N.H. –  After supporting Sen. Bernie Sanders' 2016 presidential campaign, Clarence Boston wanted to check out a fresh face for 2020.

The 29-year-old likes Pete Buttigieg’s youth, his military experience, as well as “what he says and how he says it.”

But when Boston traveled from his home in Vermont to attend a Buttigieg town hall in New Hampshire last month, one thing surprised him about the large crowd.

“I don’t see as many young people as I expected,” Boston said.

One of the oddities of the 2020 presidential contest is that Buttigieg, the youngest candidate at age 37, draws his lowest support from the youngest voters and is best liked by the oldest.

“I think he’s sort of an old soul,” said Rick Carman, a 67-year-old from Exeter, N.H., who attended a barn party for Buttigieg and likes the idea of a new generation taking the political helm.

Yet the 78-year-old Sanders, who will be the nation’s oldest-ever president if elected, continues to dominate among the youngest voters, as he did in 2016.

“I was a big fan of Bernie Sanders when I was 18 years old,” Buttigieg, who wrote an award-winning essay on Sanders in high school, told CBS recently when asked why he isn’t drawing more support from younger voters.

More:4 decades separate 2020's presidential candidates. Here's what that looks like.

From the debate:Warren criticizes Buttigieg over Swarovski crystal-encrusted wine cave fundraiser

No political analogy

It’s still early. And in Iowa and New Hampshire, the states where the previously-little known Buttigieg has spent the most time, polls show he is drawing more support among younger voters there than he is nationally. But those polls also show it’s the oldest voters who like him best and the youngest who are the least receptive.

“It’s hard to find a political analogy,” said Ruy Teixeira, co-director of the Center for American Progress’ project on demographics and democracy. “In the last 10-15 years, can we think of a candidate that young who has appealed more to older voters than younger voters?”

Even Buttigieg, who saw the same phenomenon when he first ran for mayor of South Bend, Indiana, at age 29, can’t explain it.

“It’s hard for me to understand,” Buttigieg told reporters traveling on his bus in New Hampshire last month. “But we’ve definitely noticed the pattern.”

Buttigieg on the issue:The 2020 candidate shares his views gun control, immigration, health care and more

Ideological split

Some of the difference in appeal may be ideological. 

In a December Economist/YouGov national poll of all adults, younger respondents – who are more liberal than older respondents – were much less likely than their older counterparts to describe Buttigieg as liberal.

That plays out on some particular issues like health care and college costs.

Sanders and Massachusetts Sen. Elizabeth Warren want to make public college free for everyone. Buttigieg would make public schools free for families earning up to $100,000, with some assistance offered to those earning up to $150,000.  Former Vice President Joe Biden backs free tuition at two-year community colleges. 

Sanders and Warren are promising "Medicare for All." Buttigieg and Biden would build on the 2010 Affordable Care Act by expanding subsidies for private insurance and adding a government-run plan.

Health care:Here's where the Democratic presidential candidates stand

More:Bernie Sanders calls Pete Buttigieg's health care plan 'a failed idea'

Younger voters are more likely to back a single-payer health care system while older voters are more supportive of keeping the current arrangement, said Mary Snow, a polling analyst with Quinnipiac University Poll.

“That’s one of the issues that gives us a little bit of insight into perhaps one of the reasons why he has stronger numbers among older voters than younger,” Snow said.

Universal health care and college affordability are the two issues Spencer Armstrong, a computer science student at the University of Iowa, mentioned when asked why he’s leaning towards backing Sanders in the Democratic caucus.

Revolutionary battle cry v. calmness

But some of Sanders’ appeal is also stylistic.

“He’s very to-the-point and not taking any half stances,” said Armstrong, 21. “He’s fully saying what he intends to do.”

On the flip side, Juliana Stevens, a retired teacher from Alstead, N.H., who has been volunteering for Buttigieg’s campaign, prefers the way Buttigieg answers questions in a “reasoned and calm manner.”

“They yell at you,” Stevens said of Sanders and Warren. “They yell their ideas.”

Buttigieg, said political science professor Dante Scala, is an older person’s idea of how a younger politician should behave.

“I think, for younger voters, he’s more of a student council or a student government type: very earnest, very serious, very interested in the inner mechanics of government,” said Scala, who teaches at the University of New Hampshire. “I don’t know if all of that necessarily is an attractive and enthralling package to your average 20 -year-old.”

Among the top Democratic candidates, Buttigieg had by far the highest net favorability among likely Iowa Democratic caucusgoers over the age of 65 in the November Des Moines Register/CNN/Mediacom Iowa Poll.

“He seems so wise, and he’s the young one,” retiree Kathleen Kennedy said after hearing Buttigieg speak at a July forum in Council Bluffs, Iowa, hosted by AARP.

Will it be Buttigieg, Biden or Bernie?:Here are the oldest, youngest presidential candidates in history

But in a Economist/YouGov national poll taken Dec. 1-3, a quarter of Democratic voters aged 18 to 29 said they’d be “disappointed” if Buttigieg became the nominee, his worst showing of any age group.

“Young people are ready for a political revolution,” Sanders tweeted this month when a new Quinnipiac University national poll showed him the favorite of more than half of Democratic primary voters under 35.

Buttigieg senior adviser Lis Smith, on the other hand, recently drew attention to the fact that Finland’s new prime minister, who is 34, will be the youngest in the world. The campaign likes to point out that the prime ministers of France and New Zealand were also in their 30s when they took office.

“Trend of 30-somethings coming into power across the globe continues,” Smith tweeted. “Next up: here!” 

A repeat pattern

Buttigieg, who would be the nation’s youngest-ever president, was the youngest mayor of a city of 100,000 or more when first elected in 2011 to the post he is about to leave.

When Julie Chismar, a teacher at Buttigieg’s high school, campaigned for him in 2011, she found that the oldest voters didn’t have a problem turning the city over to a 29-year-old.

“They said, 'It’s time,’” Chismar said in a 2017 interview when Buttigieg unsuccessfully ran to lead the Democratic National Committee. “Fresh ideas. New energy. They didn’t even balk at that.”

Polling in the race showed that the older the voter, the more likely he or she viewed Buttigieg’s age as a “positive.”

“To this day, I wonder why,” Buttigieg wrote in his memoir, “Shortest Way Home.” “Is it that senior voters are less likely to see distinctions between twenties, thirties, and forties? Did I remind them of their children? Whatever the reason, we took the data as a reminder that you should never assume who will or won’t support you.”

Generational change pitch

When Buttigieg launched his presidential campaign in April, the nation’s first millennial presidential candidate pitched a message of generational change. Who better to address top issues of the era than the candidate who grew up with school shootings and will face more of the consequences of climate change? 

“I think it’s part of how our campaign has gotten traction, is older generations thinking about what’s next and what kind of future they want to leave," Buttigieg told a student reporter in New Hampshire.” 

While Buttigieg has been battling Warren as the favorite candidate of college-educated voters, he’s primarily competing with Biden for the oldest voters.

“Mayor Pete has vaulted into the top tier largely on the strength of two constituencies,” Democratic strategist David Axelrod recently said on his podcast, Hacks on Tap. “Weirdly, the youngest guy in the race is now challenging Biden for older voters.”

Competition for older voters

Buttigieg's strength among older voters has been a trend in several polls, both nationally and in early states, over different lengths of time and among different sample groups.

In Quinnipiac University’s national polls taken in the first half of December, Biden was the top choice of voters 50 and older and Buttigieg was second.

In the November Des Moines Register/CNN/Mediacom Iowa poll in which Buttigieg led the field, he also was the favorite among voters 55 and older, and among likely Democratic caucusgoers between ages 35 and 54.

A WBUR poll in New Hampshire released this month showed Buttigieg and Biden neck-and-neck overall, with Biden leading among the oldest voters and Buttigieg doing the best among voters age 45 to 59.

It’s not uncommon for older voters supporting Buttigieg to say of Biden and Sanders that they can’t imagine leading the nation at that age.

“He’s like me,” Gaye Yanuszewski, a 74-year-old from Manchester said of Biden. “He forgets a lot.”

Connie Richardson, a 73-year-old retiree from Cedar Rapids, Iowa, who plans to caucus for Buttigieg, said Biden would probably do a good job if elected president. But, she added: “I think he’s got to be tired.”

“No matter how fit you are and how much you work out, how healthy you are, age takes a toll,” she said.

But when a retired farmer told Biden at a New Hampton campaign event this month that he’s too old to be president, Biden challenged him to a push-up contest.

"Look, the reason I'm running is because I've been around a long time and I know more than most people know, and I can get things done. That's why I'm running," Biden said. "And you want to check my shape, fine. Let's do push-ups together here, man."

Buttigieg faced his own challengers at a recent town hall in Coralville. Three three young protesters criticized his climate change plan for not going far enough and pointed out that he’s drawing little support among black voters in South Carolina. 

“Climate plan fatally lacking” read one of the banners. “We need more than Pete.”

Acknowledging the protesters, Buttiigieg said his campaign welcomes and hopes to win over "anyone not yet with us." Then, he added, “I would humbly suggest” the protesters lift their candidate up rather than attacking others.

Pros and cons

Doing well with older voters can be an advantage since they’re more likely to both register to vote and show up at the polls.

That’s particularly true in Iowa, where U.S. Census Data shows that  77% of people aged 65 and older voted in the 2018 general election, the second-highest rate in the nation.  

South Carolina, another state that votes early in the presidential primary, also ranks high in the share of 2018 voters who were older.

Buttigieg lags far behind Biden in South Carolina, however, because of his lack of support among African American voters and Biden’s dominance of that demographic.

“You can win a nomination with older voters if you have a larger coalition,” Joe Trippi, a veteran Democratic strategist, said in an interview. “But you can’t win it if you are as low as (Buttigieg) is with the African American community." 

Still, Trippi cautions that it’s early and allegiances will continue to change, particularly after the first votes come in in Iowa.

“It’s unwise to try to project where they are today with where they’re going to be two days after Iowa,” Trippi said. “People's’ doubts are answered or people have greater doubts about the frontrunner.”

If Buttigieg does manage to capture the Democratic nomination through the support of older voters while younger voters remain cool to him, that would be both good news and bad news for Democrats, according to Teixeira at the liberal Center for American Progress.

“The Democrats would very much benefit from doing well among older voters who are a larger share of the voting electorate,” he said. “On the other hand, young voters at this point are really much more part of what you might call the Democratic base.”

More to prove to the youngest voters

Andrew Couch, who named Buttigieg as his top choice in the November Des Moines Register/CNN/Mediacom Iowa poll, said in an interview that he does find it a “little odd” that many younger voters who supported Sanders in 2016 haven’t moved on as he has. Sanders' age is a concern to Couch, a 21-year-old studying business analytics at the University of Iowa who wants a nominee who would be able to serve for two terms.

Asked about the "coolness" factor of the candidates, Couch said Buttigieg does have a bit of a “Boy Scout vibe.” But he’s not sure if that’s a bad thing or a good thing. 

“When people want to serve in government, they want to support the community,” he said. “It takes a certain type of person to do that.”

Buttigieg told the Register that his campaign has to demonstrate “that we’re solving these issues that impact young voters, my fellow voters, more than anyone.” 

As for why that’s an easier sell to older voters, Buttigieg concluded: “I think that maybe the virtues of age and experience are a little bit demystified for voters who have more of it.”

Contributing: Mark Nichols, USA TODAY and Zachary Oren Smith, Iowa City Press-Citizen.

On the bus:Pete Buttigieg talks stress dreams, misconceptions, ‘just in case’ letter to parents

2020 candidates on the issues:A voter's guide to where they stand on health care, gun control and more