Most candidates coming off two weeks of being on the losing end of more than a dozen primaries would start looking for a graceful exit.

But Bernie Sanders isn’t most candidates, his top supporters insist. Sanders isn’t getting out of the race after being pummeled Tuesday in Michigan, a state he won four years ago, where he was supposed to show his power with working-class Midwestern voters. He won North Dakota, but lost three others to former Vice President Joe Biden on Tuesday — Missouri, Mississippi and Idaho — and the race is too close to call in Washington, another state Sanders won big in 2016.

Sanders isn’t Pete Buttigieg or Amy Klobuchar, who endorsed Biden after suspending their campaigns just as California and 13 other states were about to vote on Super Tuesday. And most important, his focus isn’t about one campaign. Sanders is focused, he says, on “building a movement.”

You don’t suspend a movement. It goes on forever.

“It’s not just about winning one election or winning the presidency,” said Brandon Harami, co-founder of SF Berniecrats and a California Democratic Party delegate. “This is about winning working-class power and winning progressive seats.”

Harami added, “People seem to think that if they wrap this up quickly, then suddenly all of us will go away. We’re not going anywhere. We’re going to be loud and active in pushing our agenda.”

That’s why Sanders is looking forward to Sunday’s debate with Biden in Arizona. The one-on-one matchup will let him show voters that his brand of democratic socialism is different from what the Democratic Party establishment is offering.

In reiterating his determination to stay in the race Wednesday, Sanders said he would ask a series of direct questions of Biden in the debate, highlighting their differences on issues including Medicare for all, free college tuition and drastic action to control climate change.

“Donald Trump must be defeated, and I will do everything in my power to make that happen,” Sanders said. At Sunday’s debate, “The American people will have the opportunity to see which candidate is best positioned to accomplish that goal.”

Sanders might not bow out no matter what happens in next week’s contests in Arizona, Ohio, Florida and Illinois — four states he lost to Hillary Clinton in 2016. Sanders kept campaigning then all the way through the Democratic National Convention, even though he was behind in the delegate count.

Four years ago, Sanders was able to leverage his support to convince the party to pass a platform at the convention that was laden with progressive planks such as establishing a $15-per-hour federal minimum wage and setting a price on carbon emissions. That scenario is set to be repeated at the party gathering in July in Milwaukee.

Many Sanders backers aren’t ready to give up yet.

Suggestions that Tuesday’s blowout was “Sanders’ last stand” amount to “calling the game at halftime,” said Maurice Mitchell, national director of the Working Families Party, a progressive political party with a presence in 18 states. It endorsed Sanders this week.

To the believers, there is no reason for Sanders to quit when Biden is just 160 delegates or so ahead of him.

“It boggles the mind to think that he would (end his campaign) at this particular point in the election cycle, when we’ve faced outcomes that no pundit could have pre-figured,” Mitchell said.

“Just a few weeks ago, they were talking about the ascendancy of Mayor Pete,” Mitchell said. “Then it was Amy Klobuchar’s momentum. Then it was the hostile takeover of the Democratic Party by Bernie Sanders. Then after that, it was the inevitable nomination of Joe Biden. In a cycle that has been this wacky and volatile, it’s presumptuous to dictate what the future might hold.”

Sanders’ supporters don’t expect him to behave like the 10 other vanquished Democratic candidates who have endorsed Biden, the latest being Andrew Yang on Tuesday night. Sanders is at a different stage in his career than, say, the 38-year-old Buttigieg, who has his political future to consider.

“For a Mayor Pete, who has a long career in front of him within the traditional Democratic Party pipeline, he has to figure out his place in that infrastructure,” Mitchell said. “Whereas Bernie is critiquing that (Democratic Party) infrastructure.”

And Sanders’ backers believe he has the best answer for the nation’s most immediate problem, the novel coronavirus pandemic. His signature issue —a single-payer, government-run health care system — is what the nation needs to handle the outbreak, said RoseAnn DeMoro, former head of the National Nurses United union and a longtime Sanders confidant.

“Every issue that the media is crying out on, telling us we are in trouble, is what Bernie has been saying for years now,” DeMoro said. “So no, I am not willing to cede that it is OK for the pundit class owned by the wealthy to declare the only campaign that represents the actual working people is over.”

Other groups that support Sanders, however, are trying to balance their enthusiasm with the growing political and mathematical realities of the campaign. The co-founder of the Sunrise Movement, the environmental organization led by young people, reminded supporters before Tuesday’s results that the Sanders-backed Green New Deal — which calls for the U.S. to run on 100% renewable energy within 10 years — “ is bigger than any one candidate or election.”

“We will fight like hell to elect Bernie Sanders, but the tough reality is that this is a super-close primary and it could go either way,” Varshini Prakash told supporters on a conference call Sunday. If Sanders isn’t the nominee, she said, then “we need to push Biden to be a stronger candidate, more capable of motivating young and climate-concerned voters should he be the Democratic nominee.”

Much of the Democratic establishment was muted Tuesday night, not wanting to risk alienating Sanders’ supporters by appearing to push him out of the race. Many Democrats remember what happened four years ago, when one in 10 Sanders primary voters — 1.5 million people — voted for Donald Trump in the general election, according to a 2017 Tufts University study.

Some asked for more detail on how Sanders primary voters behaved in general. This graphic shows this, including small % who abstained 2/n pic.twitter.com/iOjKr7eoYJ — Brian Schaffner (@b_schaffner) August 23, 2017

But one Democratic group wasn’t shy about its intentions. American Bridge, a super PAC funded by large Democratic donors and labor organizations, said it would end its neutral position in the primary and spend $2.2 million on ads for Biden in battleground state Pennsylvania.

Biden himself sounded a conciliatory note Tuesday night in a speech in Philadelphia.

‘I want to thank Bernie Sanders and his supporters for their tireless energy and their passion,” Biden said. “We share a common goal, and together we’ll defeat Donald Trump.”

Joe Garofoli is The San Francisco Chronicle’s senior political writer. Email: jgarofoli@sfchronicle.com Twitter: @joegarofoli