FRANKLIN, N.H. — Bernie Sanders is more than happy to remind New Hampshire about his big win in the state’s Democratic presidential primary almost four years ago.
To hear the Vermont senator tell it, it was promises of a $15 hourly minimum wage, free tuition to public colleges and “Medicare for all” that powered his 22-point victory over Hillary Clinton and fueled a strong underdog bid for the 2016 nomination.
“The stuff that I’m telling you today is what I told people in Vermont 30 years ago, all right?” Mr. Sanders told a crowd at Franklin High School on Saturday. “And if elected to be president of the United States, you know what, I’m probably too old to change my views.”
Now Mr. Sanders, 78, is running on a nearly identical platform, a greatest hits catalog of his progressive policy items, many of which have been adopted by his rivals. But the magic of his 2016 New Hampshire effort hasn’t fully returned.
The crowds here are smaller, key endorsers remain on the sidelines and his supporters, after three years of stewing about what many believed to have been a rigged primary contest, are wondering why he’s not doing better. In September, the campaign replaced its New Hampshire state director and chief strategist.
New Hampshire is as close to a must-win state as Mr. Sanders has, and winning is far from a sure thing right now.
Mr. Sanders gauges how well he is doing in large part based on the size of his crowds and his status in polling. He’s trailed Senator Elizabeth Warren of Massachusetts, his chief rival for progressive voters, in seven of the last eight public polls of New Hampshire Democratic primary voters. And on Saturday night, in a sign that his campaign cannot rely on New Hampshire voters to fill up New Hampshire events, his campaign invited union members from across New England to fill all the seats at a labor dinner in Manchester, for which it provided a steak-and-potatoes meal and a drink ticket.
Earlier in the day, attendees filled the seats set up inside the Franklin High gymnasium but there were only a few dozen people standing, leaving plenty of empty space.
“Four years ago this place would have been filled up tight,” said Adison Lintner, the chairman of the Franklin Democratic Committee.
Mr. Lintner, a 26-year-old real estate agent who voted for Mr. Sanders in 2016, said local Democrats who backed the Vermonter then are now split between him, Ms. Warren and several other candidates, including former Vice President Joseph R. Biden Jr., Mayor Pete Buttigieg of South Bend, Ind., and Senator Amy Klobuchar of Minnesota.
Aides to the Sanders campaign said they never expected Mr. Sanders to replicate his 2016 crowds, when he was in a binary contest against Mrs. Clinton and the Democratic Party establishment and carried the mantle of change with promises of a “revolution.” With the former New York City Mayor Michael R. Bloomberg’s entry into the race Sunday, Democratic primary voters have more than a dozen other candidates to choose from.
Faiz Shakir, Mr. Sanders’s campaign manager, said he has encouraged voters who backed Mr. Sanders in 2016 to go see other Democratic candidates’ campaign events. He said he is confident Mr. Sanders’s 2016 coalition will return to him before the Iowa and New Hampshire contests in February.
“Everyone came in like December, January and boom,” Mr. Shakir said of the 2016 race. “That is what we’re on the path to right now.”
Four years ago, Mr. Sanders had little competition for progressive Democrats. Now he has Ms. Warren competing for voters motivated by Medicare for all, Representative Tulsi Gabbard of Hawaii appealing to those who oppose foreign entanglements and the businessman Andrew Yang cleaving away voters who want someone from outside the established political system.
At the same time, New Hampshire’s independent voters, who had a choice between voting in either of two competitive party primaries in 2016, may find themselves casting ballots for centrist Democrats rather than participating in a Republican contest that is a foregone conclusion.
And the army of young voters who backed Mr. Sanders by a 67-point margin could be impacted by a new law the state passed making it harder for college students to register to vote at campus addresses.
Mr. Shakir said the Sanders campaign is aiming to win New Hampshire with about half as much support as it did in 2016.
“You’re talking about trying to get to somewhere around 30, 33 percent of the vote,” he said.
Yet there are signs of concern in New Hampshire, beginning with a dip in enthusiasm. According to the campaign’s own numbers, Mr. Sanders drew 277 people to Franklin on Saturday, about 100 fewer people than an event in August 2015 in the same community.
Tables at the Saturday night labor dinner were filled with out-of-state allies who received invitations the weekend before. At one table there were 10 unionized graduate students from Harvard University. Board members from the Maine State Nurses Association sat at another table. Nearby were officials from the union representing Environmental Protection Agency workers in Boston.
Brittany Rhodes, the president of a Vermont branch of AFSCME, the public employees union, said she was surprised to receive an invitation.
“I said, ‘Did you mean to send this to me?’” Ms. Rhodes said. “I live in Vermont.”
A Sanders campaign aide said 80 percent of the dinner’s crowd was from New Hampshire. But interviews with 30 attendees turned up just two New Hampshire voters — a couple from Durham whose daughter is interning for the Sanders campaign. They said they like Mr. Sanders but have not committed to voting for him.
“I’m thinking about Bernie, Warren, Biden and Klobuchar,” said Kathy Duderstadt, a research scientist at the University of New Hampshire. “A lot will depend on who is doing better in the polls.”
Mark MacKenzie, a former president of the New Hampshire AFL-CIO who was a key Sanders ally in 2016 and is backing him again, said formal labor support has been slow to materialize. Local unions, he said, are talking to many of the presidential candidates and waiting to endorse, if they do so at all.
“It feels different from the last time,” he said, while Mr. Sanders stood nearby in a photo line. “With so many candidates in the race it became really difficult to mine local unions. When you’re trying to build events like this it’s more difficult to do.”
Mr. Sanders has made adjustments that acknowledge the changed reality. Though he favors large rallies, this time he scheduled town-hall-style events, taking questions from the audience and staying afterward for photo lines as most of his 2020 rivals do.
He’s incorporated more local color into his remarks. When asked a question about climate change on Saturday in Franklin, Mr. Sanders responded with a warning about Granite State moose.
“Right now in New Hampshire your moose population, as I understand it, is suffering,” he said. “You know why? Because with the warmer weather, there are more ticks. And ticks are draining the blood out of moose.”
Important 2016 Sanders allies in New Hampshire remain undecided in the 2020 primary.
Andru Volinsky, a New Hampshire executive counselor who was a local lawyer for the 2016 Sanders campaign, is for now on the sidelines.
“He is one of 20 or 30, and last time he was one of two,” Mr. Volinsky said of Mr. Sanders. “I think that makes a huge difference.”
Mr. Volinsky, who is himself running for governor, said he’s more concerned with nominating a progressive candidate than who that candidate might be. “There are a couple of us who look at the polling of Warren and Sanders combined and don’t look at them separately,” he said.
Some of Mr. Sanders’s most loyal New Hampshire supporters are worried about the strength of Ms. Warren, who like him represents a neighboring state.
In Franklin, a supporter who called herself an “avid Bernie fan” begged him to “take more time to show the differences between you and Elizabeth Warren and some of the other candidates that are running against you.”
Mr. Sanders replied: “Of course I will differentiate myself from Elizabeth and the other candidates.”
And on Sunday in Hillsborough a woman complained to Mr. Sanders that he was not getting a fair shake in the news media.
“They decide who to shove down our throats,” she said. “Whether it was, no offense, Hillary Clinton a few years ago, now maybe Elizabeth Warren and then they’re going to move to Pete.”
Mr. Sanders responded with a reminder that he received only a single newspaper editorial page endorsement in 2016 and said, “I’m not the candidate of the corporate media.”
After Mr. Sanders concluded his remarks at the labor dinner with a call to dance — “I think we’re going to do some dancing in a while. Our revolution includes dancing” — aides moved to hustle reporters out of the space.
Following appeals to watch the senator, who is nearly eight weeks removed from a heart attack, hit the dance floor, the campaign relented. Mr. Sanders later hit the dance floor to three songs: “The Way You Do the Things You Do” by The Temptations, “I Can’t Help Myself” by the Four Tops, and “Dancing Queen” by Abba.
Mr. Sanders avoided the reporters standing a few feet away chronicling his moves on the dance floor. Later, he retweeted several videos they posted to Twitter.
“Having the time of my life,” he wrote.