The room at Southern New Hampshire University in Manchester had 400 seats set out for Bernie Sanders’ town hall meeting on Saturday; all of them were full and people were standing in the aisles. They’ve come for the message Sanders has been delivering with the consistency of a jackhammer for his whole political career.

Broadcast version

“Today, well over 50 percent of all new income is going to the top one percent,” Sanders intoned from behind a podium. “You are living in a rigged economy where the rich get much richer, everybody else gets poorer and together, we are going to change that."

Sanders packed a busy schedule of campaigning into this weekend visit, his first to New Hampshire in over a month. In the time since, Sanders stock has risen considerably, and he has emerged as the main challenger to Hillary Clinton.

Now the challenge for the Sanders campaign is how to turn its most abundant resource – enthusiastic volunteers – into electoral success.

Infographic: The Anatomy of the Sanders 2016 Campaign

Sanders platform is straight from a progressive’s wish-list: publicly funded college and elections, $15 an hour minimum wage, aggressive action on climate change, and paid family and medical leave for all.

That message is getting plenty of attention this campaign season. Recent polls from Gallup, Marist and Quinnipiac found that in Iowa, New Hampshire and nationally Sanders is the only candidate of either party that more people view favorably of than unfavorably. And all of his meetings this weekend – events in Exeter, Franklin, Claremont, and Rollinsford – were standing room only.

But despite the rapid rise since his announcement in May, Sanders still trails Clinton in the polls by a huge margin.

Harnessing the Enthusiasm

Last week was when what one could perhaps call the real work of his organizing effort began. Wednesday, Sanders' campaign held more than 3,000 organizing parties nation-wide – 37 of which were in New Hampshire. At those parties, perhaps as many as a 100,000 potential Sanders volunteers heard a simulcast of Bernie marshalling them from DC.

Here’s the plan: Sanders has less money than Clinton and has disavowed using a super-PAC to support the campaign. So he’ll rely on people. Un-paid people.

“The only way I know that we do that is when we put together a strong grassroots movement of millions and millions of people. And that’s what I mean by a political revolution and that’s what you are involved in today,” Sanders told supporters Wednesday night.

After the video finished, and an aide named Claire Sandberg stepped up with a number that supporters can send a text to receive campaign assignments.

“We need you to bring this movement to your community by doing unglamorous but essential work, like knocking on doors, calling voters, voter registration,” she told the organizing parties.

This is how the Sanders campaign is hoping to turn big crowds into something more concrete: success at the polls.

“It’s not staff driven. The staff can help organize folk,” said Kurt Ehrenberg Sanders’ campaign manager in New Hampshire, “but we are now going to create local teams all across the state that will have local team leaders, volunteers, these local team leaders will have a team of folks who can give a few hours a week a day a week, whatever it may be.”

Sanders’ campaign has the biggest staff in Iowa. Perhaps in part because getting people to caucuses is a hassle logistically, but also because maybe Sanders is expecting an easier time with name recognition in neighboring New Hampshire.

There is also paid staff at headquarters in Burlington, a small operation just starting in South Carolina, and Ehrenberg said they’ll begin hiring in Nevada soon.

The staff will function as organizers, funneling canvassing maps and voter lists out to local leaders. States with no staff will be talking directly to Burlington. Ehrenberg said volunteers will reach out to other volunteers, trying to get them to move up a so-called “ladder of engagement”

“Someone gets in touch with them, asks them to come to a local meeting. They come to the local meeting they say, ‘yeah I could take a clipboard to the farmers’ market Saturday morning.’ So they do that,” he said. “You know, they’re engaged, they get more enthusiastic and they bring other people in and that’s a grass-roots movement.”

Broadening the Appeal

Sanders is not the only candidate planning on this kind of organizing – campaigns have been getting serious about engaging volunteer organizers following Obama’s coup in 2008. The difference is that volunteers will likely be by far the greatest asset the Sanders campaign has.

But there is a major hurdle that the effort will need to clear if it has any hope of prevailing over Clinton. The challenge is to broaden Sanders' appeal beyond his core of committed supporters.

“I think a big thing for me is that I see all these countries outside the United States – Denmark and Sweden and all those countries – they have awesome services for their people that live there,” said Gabby Teed who turned up for that organizing meeting in New Boston. She and her mother both have tattoos all up and down their arms and say caring for the under-served is their number one issue. “We’re supposed to be the greatest country, and I hate to say that we’re not,” she says.

At this particular meeting socialist is not a dirty word for many in attendance, and in the parking lot there is a camper van covered with bumper stickers that say “Corporations are not people,” and “Don’t tread on my Obamacare.”

It’s not yet clear if Sanders can appeal to more than just the most progressive Democrats and attract a broad coalition of voters like the one that delivered Barack Obama the Democratic presidential nomination in 2008.

A Washington Post poll from mid-July finds that Sanders is viewed less favorably by non-white Democratic voters, though a large portion still have no-opinion of him as well. Clinton, on the other hand, actually does better with non-whites.

“We have work to do to, frankly, get Bernie more well known in some other parts of the country with some other demographic groups. So we understand that and we’re working on that,” Ehrenberg acknowledged.

To that end, Sanders added a new section to his stump speech this weekend, focusing on racial injustice and police violence. If that work doesn’t bear fruit, Sanders campaign may also struggle to attract another potential type of voter to his coalition. People like Beth Widmayer,

"I think philosophically, I'm with Bernie all the way. It's just the practicality of his candidacy, I guess, is a little bit of an issue with me."

“I’m a little reluctant to buy in on the Hillary message because I think it’s more or less expedient right now for here,” Widmayer explained at the organizing party in New Boston.

She says income inequality is her number one issue, but can’t commit to Sanders yet. “I think philosophically, I’m with Bernie all the way. It’s just the practicality of his candidacy, I guess, is a little bit of an issue with me,” she explained.

“…Beyond your zone of comfort…”

Sanders’ volunteer driven effort has between now and February to gather enough momentum to persuade voters like Widmayer that he will be a viable candidate in the general election.

“But our job, brothers and sisters is to create a political revolution,” Sanders told the crowd in Manchester – where apart from signing up a few hundred new potential volunteers as they walked in the door of his town hall, Sanders had a big ask. “It means going out beyond your zone of comfort. It is easy to talk to your family and friends and people who agree with you. It is a lot harder to reach out to good people who disagree with you. And that is what our job is,” he implored the crowd.

Just how far beyond their zone of comfort the volunteer driven Sander campaign can push itself is the big question. And the answer will play itself out as the organizing begins in earnest over the coming months.