LAS VEGAS — Revolutionaries are underdogs — until they are not.

Such is the case with Bernie Sanders, who is now the leading contender for the Democratic Party’s presidential nomination. Sanders is the favorite to win the Nevada caucuses, a feat that would provide momentum as the presidential primary heads to South Carolina and then the March 3 Super Tuesday states, including Texas.

The insurgent is now the frontrunner.

“He should have been at the center all along,” said former Ohio state Sen. Nina Turner, the national co-chair of Sanders’ presidential campaign.

Turner said that frontrunner status hasn’t changed Sanders’ approach. He’s still running as a warrior for the working class, and still must endure attacks from inside and outside the Democratic Party.

“In some ways, he still is an insurgent,” she said. “He had the courage and he put forward all the issues that have animated the Democratic Party. He is still running that kind of campaign.”

How Sanders navigates frontrunner status could impact the course of the Democratic presidential race. For the moment, he’s held off Sen. Elizabeth Warren of Massachusetts as the choice of most progressives. And with so many moderates, the Vermont senator currently has the best chance of going into the Democratic National Convention as the delegate leader.

That worries many Democrats and could have aided the rise of former New York Mayor Michael Bloomberg, who has poured more than $409 million from his personal fortune thus far to win the nomination and, in the process, stop Sanders.

“I don't think there's any chance of the senator beating President Trump,” Bloomberg said at Wednesday’s explosive Democratic presidential debate in Las Vegas. “You don't start out by saying I've got 160 million people, I'm going to take away the insurance plan that they love. That's just not a way that you go and start building the coalition that the Sanders camp thinks that they can do. I don't think there's any chance whatsoever.”

Then Bloomberg voiced most Democrats’ worst fears.

“If he goes and is the candidate, we will have Donald Trump for another four years,” he said. “And we can't stand that.”

Sanders blasted Bloomberg for his support of the stop-and-frisk policing policy that targeted blacks and Hispanics, while defending his crusade.

“What our movement is about is bringing working-class people together, black and white and Latino, Native American, Asian American, around an agenda that works for all of us and not just the billionaire class,” he said. “That agenda says that maybe, just maybe, we should join the rest of the industrialized world, guarantee health care to all people as a human right, raise that minimum wage to a living wage of $15 bucks an hour, and have the guts to take on the fossil fuel industry, because their short-term profits are not more important than the future of this planet and the need to combat climate change.”

Assuming frontrunner role

In 2016, Sanders spent his entire presidential campaign in second place behind former Secretary of State Hillary Clinton, the clear frontrunner and eventual Democratic Party presidential nominee.

Four years later, Democrats across the country have adopted many of his policy proposals, including Medicare for All, free college tuition, revamping the tax code and ending needless foreign conflicts.

Sanders has described himself as a democratic socialist, but that hasn’t hurt his support, especially with progressives.

A victory in Saturday’s Nevada caucuses would make Sanders hard to stop, analysts say.

“What happens to a lot of frontrunners is that they begin to play it safe,” said Mark McKinnon, a former adviser to President George W. Bush and now co-executive producer of The Circus: Inside the Greatest Political Show on Earth. “The other way is to continue to act like an insurgent and act like you’re 20 points down.”

McKinnon said that if Sanders emerges as the Democratic presidential nominee, he’ll have to unite a fractured party.

“He’s got to consolidate the party,” he said. “He’s got to lose a little bit of that ‘I’m against everybody and we’re fighting the machine.’ He’s going to be the machine, whether he likes it or not.”

The minefields that could be ahead of Sanders involve his policy positions.

His call to abolish private insurance and place everyone on a government-run system has run afoul with some unions, including the powerful Culinary Workers Union in Nevada.

“It’s a potential liability because it’s going to be on that menu of things Trump will go after him for, and it’s what his primary opponents have gone after him for,” McKinnon said. “But that’s also why Sanders is winning. He’s pure on this issue, and that’s what a lot of Democrats want. They want a revolution, not an evolution.”

The Culinary Workers Union has not endorsed a candidate in the contest, but members have posted flyers warning that Sanders’ health care plan would erase all that they’ve accomplished related to health insurance.

Sanders says they will be better off with his plan.

“Bernie Sanders Medicare for All system will give everybody better benefits at lower costs,” said Jeff Weaver, senior adviser to the Sanders campaign.

He added union workers would see their pay rise because employers would apply the savings from paying for health insurance to worker salaries. Some Democrats don’t believe that and worry about the cost of such a proposal.

On being a democratic socialist

Some Democrats fear that the term socialist, which Sanders embraces, will scare American voters into voting for Trump.

At the debate, Sanders said he was against socialism for the rich.

“If speaking to the needs and the pain of a long-neglected working class is polarizing, I think you got the wrong word,” Sanders said to an attack from former South Bend, Ind., Mayor Pete Buttigieg. “What we are trying finally to do is to give a voice to people who after 45 years of work are not making a nickel more than they did 45 years ago. We are giving a voice to people who are saying we are sick and tired of billionaires like Mr. Bloomberg seeing huge expansions of their wealth while a half-a-million people sleep out on the street tonight.”

Turner said as she campaigns for Sanders, she doesn’t hear anyone complain about his ideology or ask about being the standard-bearer of the Democratic Party.

“They care about the issues he’s putting forward,” she said. “They know he cares about working families.”

Analysts say Sanders still has work ahead of him if he wants to be a unifying figure.

While he expects to win Nevada, South Carolina and other states with large numbers of black voters could create challenges. Sanders’ standing with African Americans has risen since 2016, but he’s still lagging behind candidates like former Vice President Joe Biden.

“Can he expand his base, and can his base handle him being the frontrunner?” asked civil rights activist and political commentator Al Sharpton. “What happens if he wins in Nevada and goes to South Carolina and loses? He still isn’t where he should be with African American voters, though he’s doing better.”

Democratic leaders point out that Sanders, in many polls, is ahead of Donald Trump, and that the nation could be ready for his brand of politics.

But the race is just getting started, leading Democrats say.

“The main number to keep in mind is 1,991. That’s the number of delegates you need to win the nomination on the first ballot,” said Democratic National Committee Chairman Tom Perez. “We’re at probably mile two of the marathon. … Whoever wins I’m going to be exceedingly excited about it, whether it’s Sen. Sanders or anybody else in the field.”