(CNN) For supporters of Sen. Bernie Sanders' presidential campaign, many are asking themselves this fall, "Are you selling out if you support Hillary Clinton?"

That's the conversation progressive radio show host Arnie Arnesen said she's been having with many New Hampshire voters over the last couple months, with less than three weeks to go until the presidential election.

"Because they have a sense of ownership, they personally lost. It wasn't their candidate that lost. They lost, too," Arnesen said of the coalition of voters that brought Sanders 1,893 delegates, not enough to clinch the party's nomination.

In New Hampshire the loss was even more pronounced. Sanders won more votes than any candidate in the history of the state's primary and beat Democratic nominee Hillary Clinton by a huge margin of 22 percentage points.

Sanders trounced Clinton in New Hampshire with millennials as well as Independents, and winning over both groups will be a test of Clinton's strength as the standard bearer of her party.

In the latest national public polls Clinton appears to be doing just that -- she has opened up a lead with younger voters against Republican Party presidential nominee Donald Trump, and is splitting the independent vote with Trump.

The latest poll of likely voters in New Hampshire, from WMUR/UNH, has Clinton up 15 percentage points over Trump in the state, with 87% of Democrats consolidating behind her compared to Trump's 75% of Republicans.

According to the poll Sanders voters are more likely than any others voters to say they will vote for a third party candidate, though history suggests many will end up picking a major party candidate in the end.

But even as Sanders' coalition appears to have coalesced behind her, 53% of New Hampshire voters have an unfavorable view of Clinton and a snapshot of some of his most ardent supporters in New Hampshire hints that deep fissures remain.

Arnie Arnesen, a progressive radio show host, hosted one of Bernie Sanders early events at her house in Concord before he declared, though she never endorsed him. "Hillary Clinton is my reality. That's what I need to do. How many times have we had really good choices?"

'I don't know which one would be worse'

New Hampshire represents a particular slice of the Democratic party: It is a state that is less diverse than many in the country and one where primary voters largely ignored the local party elite's full embrace of Clinton and their rejection of Donald Trump.

"A vote for Sanders wasn't really an ideological vote. It was much more age and political independence that made key differences in whether you were going to be a Sanders voter or a Clinton voter," Dante Scala, associate professor at the University of New Hampshire tells CNN.

Scala discounts the idea that there are many true Sanders-Trump voters, although he adds younger voters tend to be the most skeptical of Clinton.

Jed Fiato, a 24-year-old graduate student at New England College, is a member of the demographic that Scala says will be one of the hardest for Clinton to attract -- young males who don't have strong party affiliation.

Fiato is an Independent and didn't vote in the 2012 presidential election, the first one he was eligible for. He was frustrated with President Barack Obama over his handling of health care reform and the economy.

Tucked away on a shelf in a closet on the second floor of the house he shares with his wife Jenny, Fiato keeps memorabilia from his time volunteering for Sanders during the primary.

Jed Fiato, a volunteer for Sanders during the primary, is not sure he will vote at all. "I could, at this point, care less if Hillary Clinton won or lost because I think that Donald Trump winning might actually be a wake-up call for the rest of the country, and a wake-up call for the Democratic Party."

He has the front page of the Concord Monitor the day after the primary, reading: "Trump, Sanders ride voter anger to victory in New Hampshire," and a "New Hampshire for Bernie" sign he held up at a 4 a.m. rally for Sanders the night of the Iowa caucuses.

"It's something I'll never forget, being there with Bernie Sanders supporters standing out in the cold in February, waiting for Bernie Sanders to arrive on his bus and him speaking to us standing on top of a pick-up truck," Fiato told CNN on a recent October night.

He does not have the same ardor for Clinton.

"When I hear Hillary Clinton speak, I do not hear someone who actually believes what they are saying," Fiato said.

At the same time Fiato said that Trump is a "menace" and "exhibits all of the character traits that I find repulsive in a person."

"We're going to have either Trump or Hillary as the President of the United States and, honestly, I don't know which one would be worse," Fiato told CNN.

Although he wavers on what he will actually do on Election Day, Fiato told CNN he plans to write in Bernie Sanders' name on the ballot if he votes at all. He is sick of the argument that not voting for Clinton is a vote for Trump.

"I can imagine a four-year presidency under Hillary Clinton where she makes policy decisions that directly contradict things that I believe in," Fiato told CNN. "I don't want to have to be confronted with someone in the future who says, 'Well, you voted for Hillary Clinton.'"

Fiato also still resents a nominee that he feels was preordained by the Democratic party establishment, a feeling shared by others Sanders supporters.

"I'm talking to a lot of people and there is not a lot of enthusiasm. People who jumped into the process and got involved that hadn't before are feeling like it doesn't matter, like it's futile, and that is wrong. It matters so much," says Mark King, a 54-year-old library worker who cites Sanders as his inspiration to run for state representative this election cycle.

Mark King, an AFL-CIO volunteer and library worker in Nashua, still struggles with how he will vote on November 8th. "If I write in Bernie Sanders, I will be doing the thing that feels right to me although it is totally futile."

King was on Sanders state steering committee and sees reasons to vote for Clinton,

"I've been voting for the lesser of two evils for a while now. It doesn't leave a good taste in my mouth, but I'm practical. I'm pragmatic," King said.

Although he told CNN he feels pressure to endorse the entire Democratic ticket because he is running for local office, King later said -- like Fiato -- he plans to write in Sanders' name on the ballot.

"This election is the most difficult thing I've ever considered," he told CNN.

'They changed the party. They changed the country'

Arnesen remembers hosting Sanders for a house party back in January 2015.

Back then few guessed he would be running for president, but Arnesen, who didn't endorse a candidate in the primary, says she wasn't surprised when his campaign took off.

"They changed the party. They changed the country. They changed the conversation. Hillary Clinton had to change on so many issues. If you don't call that winning, you're nuts," Arnesen said.

Arnesen points to the changes Clinton has made in her platform, as well as the Democratic agenda hammered out at Democratic National Convention, due to Sanders' presence in the race.

Clinton's supporters say those changes helped their efforts to bring over Sanders voters -- but that her effectiveness relies on a wide margin of support in November.

"If she gets that kind of support, including the support from Bernie Sanders supporters, then she can say look this is what the voters want," longtime New Hampshire activist and Clinton supporter Terie Norelli told CNN.

"A lot of people had given their hearts and souls to Bernie for months, and we needed a little time to heal. But we have healed, and we are passionate now about Hillary," said activist Dudley Dudley, an early key endorsement for Sanders in New Hampshire and a member of his steering committee.

"My support for Hillary is not just because I don't support Donald Trump. It's because I do support her, and the way that she has grown, and stretched, because of her contact and support from Bernie," Dudley told CNN.

Dudley Dudley, a longtime Democratic activist in New Hampshire, shares a voicemail Bernie Sanders left her after she endorsed him in the primary. "We needed a little time to heal. But we have healed, and we are passionate now about Hillary."

Although Sanders has not shared his vast donor list with the Clinton campaign he has campaigned for her in New Hampshire four times since the convention, appearing with her twice, and has been a near constant presence on the campaign trail across the country.

The Clinton campaign and Democratic party have hired Sanders staffers in New Hampshire at senior levels as well as field organizers.

Sanders' former state director and a national field director, who is now Executive Director of the Association of State Democratic Chairs, says she sees significant change.

"I see what's happening at the DNC," Julia Barnes tells CNN. "All of the changes that have happened there, while not as public as some of the missteps that have happened in the past, are legitimately setting the groundwork for some really good inclusive collaboration moving forward which hasn't always been the case."

The organization Sanders launched after his run, "Our Revolution," has been focusing on down ballot races, and has endorsed a number of Democrats running for state representative seats in New Hampshire, including Mark King.

Sanders' campaign committee "Friends of Bernie Sanders" also recently sent out a fundraising email for congressional candidates, including New Hampshire Gov. Maggie Hassan, who is running for Senate.

Many Sanders supporters see a focus on local elections and policy initiatives as the most urgent legacy of Sanders' campaign.

For Arensen, that doesn't mean that Sanders' influence on the presidency is over.

"What I would love to say to millennials is that you did lose. Your candidate lost, the person that you most committed to," Arnesen told. "But the person I think now that I want Hillary Clinton to be the most afraid of is Bernie Sanders."

"Change doesn't happen with a switch. It takes time. Hillary Clinton is smelling it, and realizing it, because Bernie showed that that's what people want," she added. "Bernie won, but he will lose if she loses. If Donald Trump wins, we all lose."