LAS VEGAS — One scorching Saturday afternoon in July, some 70 supporters of Sen. Bernie Sanders (I-Vt.) crammed into a community room at a library here for one of the campaign’s organizing sessions. The event, a reunion fraught with both anger and nostalgia for the last presidential cycle, was just a few miles from where the senator’s supporters had erupted during the state’s contentious 2016 party convention.

“We were not defeated. We were cheated!” shouted one woman from the back of the room.

“Who’s a little bit angry? . . . Who’s ready to get to work?” a campaign staffer asked the crowd, questions met with raucous applause. Among those shouting loudest was Marcia Armstrong, a 63-year-old who lives in nearby Henderson and works in customer service for a property management company. She said she was trying to find some positivity and motivation in her frustration, but others — who believe the electoral process was rigged by the Democratic National Committee three years ago — were less optimistic.

To understand how Bernie Sanders became a presidential contender, you have to start in Vermont. (The Washington Post)

“I think they’re just fed up with the whole system, and some of them feel that nothing can be done to change it. I disagree,” she said. “I try to be positive.”

In 2016, Sanders and his supporters shared a visceral anger at the nation’s economic and political systems, which they contended had been corrupted by wealthy capitalists. Hillary Clinton proved the perfect foe for an anti-establishment campaign then. But with a sitting president who has also used anger to galvanize his base and claims to represent the antithesis of the Washington elite, some now find that aggressive messaging unappealing.

The overall dynamics also have shifted. During the 2016 presidential cycle, the independent senator stood alone in his — oftentimes cantankerous and rowdy — fight for a single-payer health-care system, tuition-free four-year public college and a $15 minimum wage. Several presidential hopefuls have fully embraced his once-radical ideas without adopting his boisterous tone.

During a spat between Sanders and Rep. Tim Ryan (D-Ohio) on the debate stage in July over how best to curb greenhouse gas emissions, Ryan told the senator from Vermont, “You don’t have to yell.” Ryan’s campaign was quick to use the moment as a marketing ploy, with new stickers: “You Don’t Have to Yell: Tim Ryan 2020.”

For voters who yearn for the institutional change Sanders shepherded in during the 2016 campaign but who are turned off by his tenor, there are now options. Interviews with dozens of Democratic voters in Washington, California, New Hampshire and Nevada showed that many former Sanders loyalists are now playing the field for their 2020 vote.

Jonathan Eren, a 34-year-old software engineer from Seattle who supported Sanders in 2016, felt “cheated” when the DNC gave the nomination to Clinton. Now, Sanders is back on the campaign trail, but Eren no longer stands behind him.

“I just feel [Sen. Elizabeth] Warren has more of a better understanding of it all,” he said of the Massachusetts Democrat as he perched not far from the stage where Warren would soon address 15,000 rallygoers at a park in Seattle, her biggest event to date. Sanders beat Clinton in the Washington caucus by nearly a 50-point margin in 2016.

The two senators from New England, longtime pals who share a common enemy in Wall Street, find themselves more similar than different when it comes to policy goals, such as Medicare-for-all and student loan debt forgiveness, as well as a message of revolution and “structural change.”

Where the candidates — Sanders a democratic socialist and Warren a proud capitalist — diverge is in the tenor of their campaigns.

“It’s not as though [Warren is] content to thunder against the evildoers like an Old Testament prophet. That’s much more his mode,” said William Galston, a senior fellow at the Brookings Institution and former domestic policy adviser to President Bill Clinton. “Sanders sees [his campaign] as a revolutionary mass movement to upset the established order. While Senator Warren is obviously very dissatisfied with the status quo, she describes her campaign in very different terms and terms that I think are less scary.”

Many Democratic voters who were once attracted to Sanders’s anti-establishment message believe that the nominee ought to have a vision of unification to beat Trump in 2020.

Andrew Bauld, a 34-year-old writer who lives in Brooklyn, said that he initially liked Sanders in part because he did not believe there should be a presumptive candidate, but that his enthusiasm for the senator from Vermont faded even before the 2016 primaries ended.

Exiting a house party for the Warren campaign in Wolfeboro, N.H., earlier this month, Bauld said he was tired of Sanders’s combative tone.

“He brings it from, ‘I’m gonna yell about it, and I’m angry,’ ” he said, adding that Sanders did not do enough to unite Democratic voters behind Clinton in the 2016 general election. “Senator Warren has similar ideas but brings it in an exciting package.”

Nicholas Mathews, a 33-year-old self-employed barber from Bremerton, Wash., said he supported Sanders during the 2016 primaries but did not vote. Though he said his friends are split 50-50 between Sanders and Warren, he is now partial to the senator from Massachusetts, in part because her messaging feels “softer.”

Sanders’s approach “is a little more aggressive, and not in a ‘take stance’ sort of way, [but] in a ‘take him down’ kind of way,” he said. “He had his time.”

Sanders’s polling numbers in early-voting states such as Iowa and New Hampshire — where in 2016 he battled Clinton to a near draw and won, respectively — have dropped dramatically. Meanwhile, he continues to face pushback from former Clinton supporters.

Barbara Underwood, an 87-year-old retired state legislator who lives in Sugar Hill, N.H., said she supported Clinton in both the 2016 primaries and general elections. She argued that Sanders is partly responsible for Clinton’s defeat — a characterization that Sanders and his allies heatedly deny — and questioned whether he did enough to rally his supporters behind the Democratic Party’s eventual nominee. She worries that he could cost Democrats the upcoming election.

“I figure he was a spoiler in the last election,” Underwood said. “I think a lot of people that would’ve — maybe should’ve — voted for Clinton voted for Bernie, and that split the vote. . . . I sort of hold it against him, having done it once, maybe going to do it again.”

But many Sanders supporters resent the presumption that they were responsible for Clinton’s shortcomings. They remain angry at Clinton and other members of the establishment who they claim rigged the system against Sanders. The candidate and his campaign have leaned into that sentiment, lambasting the media for coverage they deem unfair and publishing an “anti-endorsement” list of big-money business executives and a centrist think tank opposing his candidacy.

While Sanders faces criticism for his oftentimes incendiary speeches and comments, many of his supporters see his heated tone as a mark of authenticity and dependability over a decades-long career in public office. Jennifer Convery, a 53-year-old kindergarten teacher from Gorham, N.H., who attended a Sanders town hall nearby, said the campaign’s signature anger is, in part, what makes Sanders seem stronger than other candidates in his beliefs.

“He’s mad, and you gotta be mad,” she said. “In order for things to change, there’s got to be some anger and frustration to get it done. I like Bernie’s passion. You can hear it when he talks. It’s coming from the heart.”

But the Sanders supporter is concerned that her candidate will fall short of the nomination once again. She worries that his age — 77 — will be used against him, and that other voters may be drawn to a candidate who offers the appeal of diversity.

Convery was not quite sure how Sanders could expand his voting bloc.

“He reaches out as much as anybody else as much as he can. He’s not going to change who he is and how he is, so he can’t make himself younger or black or a woman, so I don’t know,” she said. “What do you do? You’re not going to change your points.”

Sanders sees his signature ire as a point of pride. At the end of the day, the campaign is betting on the strategy to prove his consistency.

After Sen. Mitt Romney (R-Utah) questioned in a tweet why the senator from Vermont was so angry, Sanders responded with the slight: “I’m angry because multi-millionaires like you and Trump have rigged our economy at the middle class’ expense. I’m angry because millions are living paycheck to paycheck. I’m angry because 34 million Americans are uninsured.”

He asked the Republican senator, just as his campaign asks Democratic voters, “Why doesn’t that anger you?”