MANCHESTER, N.H. >> Bernie Sanders turned his outsider credentials and call for political revolution into a commanding victory in the 2016 New Hampshire primary. But as he seeks a repeat performance, the Vermont senator could face unlikely competition.

On their own, Andrew Yang, Hawaii Rep. Tulsi Gabbard and Marianne Williamson sit near the bottom of the New Hampshire polls. But together, their novel calls for dramatic change to American politics could attract just enough support to complicate Sanders’ path to victory in a tight New Hampshire race.

“There could be six points there that Bernie loses,” said veteran Democratic operative Mark Longabaugh, who previously worked for Sanders. “That could be all the difference in the race.”

The three candidates are each at about 1% in a July poll from the University of New Hampshire and CNN. It’s not clear that any of that support comes from voters who would otherwise back Sanders.

And Sanders is facing a much stronger challenge for progressive support from Elizabeth Warren, who is bunched near the top of most New Hampshire polls with Sanders and Joe Biden.

But the dynamic is a reminder of the different environment Sanders is competing in during his second presidential campaign. In 2016, he was the sole progressive alternative to Hillary Clinton, and his 22-point victory in New Hampshire added much-needed credibility to what was considered a longshot candidacy. He’s now one of 20 Democratic White House hopefuls, many of whom are using his rhetoric to appeal to the liberal base.

If Sanders is worried, he isn’t showing it. He laughed when asked over the weekend whether he was concerned about losing support to bottom-tier rivals.

“You live in a free country,” he said. “Marianne and Tulsi are friends of mine, and they’re running hard, and they have every right to run so it’s not my job to tell people what they can do and not do. But they are serious people and they’re running good campaigns.”

Sanders is facing sky-high expectations in New Hampshire, in part because he’s from neighboring Vermont, has raised millions of dollars from grassroots donors and is one of the most recognizable names in politics.

But there are warning signs for Sanders. The progressive Working Families Party endorsed Warren today after backing Sanders in 2016.

Sanders was slow to build a large campaign staff in New Hampshire, and Warren is credited with having a stronger organization in the state.

Over the weekend, Sanders’ campaign stepped up efforts to avoid what would be an embarrassing loss in New Hampshire. The New Hampshire state director was replaced, and another senior adviser said he’d leave in a separate move.

The campaign has attempted to expand its 2016 coalition in New Hampshire, with hopes of winning over Clinton voters and independents. Results, however, have been mixed.

Before the New Hampshire Democrats’ state convention earlier this month, the Sanders campaign announced a lengthy list of endorsements, including one from state Rep. Wendy Chase, a Rollinsford Democrat. But Chase said following the convention that publicizing her endorsement was premature and that she is still considering whether to vote for Sanders, Warren, Yang, or for South Bend, Indiana, Mayor Pete Buttigieg.

The developments are fueling a sense among voters that, while Sanders might have revived the progressive movement’s starring role in Democratic politics, he may not be the person to lead it in 2020.

“Unfortunately, Bernie’s time has come and gone,” said Kevin O’Neill, a 64-year-old attorney who supported Sanders in 2016 and is now leaning toward a vote for Gabbard. “He’s done a great service to the country, a great service to the party. But I think at this point, he needs to pass the baton on to a new generation.”

While Gabbard, Yang and Williamson have much smaller followings in New Hampshire than Sanders, they’ve made investments in the state.

The most recent campaign filings this year show Williamson has paid more than $65,000 in New Hampshire to employ Paul Hodes, a former congressman, who works as her New Hampshire state director and senior campaign adviser.

Campaign finance records also show that, through June, Yang’s campaign has paid $60,000 for Steve Marchand’s services. Marchand, the former mayor of Portsmouth and past candidate for governor who backed Sanders in 2016, is advising Yang and campaigns for him in the state.

Gabbard has opted for campaign billboards that leave some voters puzzled: They include only her first name, a picture of her, the year 2020 and the words “A Soldier’s Heart.”

Whatever impact the candidates might have on Sanders will depend on how long they stay in the race. For now, only Yang has qualified for next month’s presidential debate. But no one is signaling an imminent departure from the campaign trail.

Gabbard insisted she would not drop out during a recent campaign stop in New Hampshire, while Williamson simply said, “All I know is that, right now, I’m running for president.”

She was effusive in her praise of Sanders in an interview after leading a meditation on peace in Manchester.

“I love Sen. Sanders. … He’s an inspiration,” Williamson said. “He’s marvelous.”