Senator Bernie Sanders of Vermont was reassessing the future of his presidential bid on Wednesday after a crushing round of primary losses left him with no realistic path to the Democratic nomination and the 2020 race itself was on hold because of the coronavirus outbreak.
Mr. Sanders’s campaign has stopped actively advertising on Facebook, and his campaign manager sent an email to supporters without asking for donations — the kind of steps that sometimes precede the end of campaigns. His aides say Mr. Sanders is not suspending his bid, even as some Democrats have become increasingly vocal that he should consider leaving the race.
The party’s front-runner, Joseph R. Biden Jr., has now amassed a nearly insurmountable lead in delegates needed to clinch the nomination after winning the Arizona, Florida and Illinois primaries on Tuesday. Mr. Biden has swept so many states and attracted so many demographic groups that Mr. Sanders has little left to go on besides his political message and his passionate base of liberal supporters.
Some Democrats said that with the delegate outlook so bleak, and with a deadly pandemic gripping an anxious nation, Mr. Sanders risks appearing self-centered and out of step if he insists on pressing ahead.
“Bernie is getting beat by 30 and 40 points — it’s over,” said Representative Don Beyer of Virginia, who has endorsed Mr. Biden. “This is the adult thing to do — knowing when it is time to disappear.”
Mr. Sanders, who has not said when he will make an announcement about his future, was testy on Wednesday when asked by a CNN reporter about his plans, suggesting his sole focus should be on the virus.
“I’m dealing with a fucking global crisis,” he said at the Capitol. “You know, we’re dealing with it, and you’re asking me these questions.”
“Right now, I’m trying to do my best to make sure that we don’t have an economic meltdown and that people don’t die,” he added. “Is that enough for you to keep me busy for today?”
Some Democrats said Mr. Sanders had already accomplished a great deal by promoting his liberal policy agenda. Yet they warned that staying in the race could damage the coalition he has built since 2015.
“It’s time to throw in the towel knowing that he has won the battle of issues,” said Wilbur Colom, a Democratic National Committee member from Mississippi who formerly supported Michael R. Bloomberg. “The Democratic Party has moved within inches of his revolution on all major issues.”
Yet 26 states, territories and the District of Columbia have yet to hold primaries and caucuses, and there are still 1,399 delegates left to be awarded. With the primary season essentially on hold because of public health concerns, it could be at least two months before Mr. Biden accumulates enough to secure the nomination. D.N.C. rules require a presidential nominee to accrue 1,991 delegates, and Mr. Biden cannot win those delegates if states don’t hold their primaries.
But if Mr. Sanders does quit, Mr. Biden would be free to move on to focus on the general election, President Trump and the national challenges posed by the virus.
Even among those who view Mr. Biden’s eventual triumph as inevitable, there is a belief that contested primaries are good for the party, generating enthusiasm and spurring turnout. In Wisconsin, Democratic officials worry that if Mr. Sanders drops out before the state’s planned April 7 primary, it could depress turnout and hurt liberal candidates for state and local offices.
“There’s thousands of people on the ballot right now,” said Andrew Werthmann, a D.N.C. member from Eau Claire, Wis. “People should recognize that having contested primaries does help drive turnout and that helps all elections down the ballot.”
Others in the party say that prodding Mr. Sanders to drop out now would deprive his loyalists of the right to show their support for him at the ballot box. And for the party’s left wing, having Mr. Sanders continue to run would enable them to win delegate slots at the national convention, which would provide leverage when it comes to shaping the party’s platform and writing rules for the next presidential nominating contest.
“Bernie is not running a campaign so much as leading a movement,” said Winston Apple, a D.N.C. member from Missouri who supports Mr. Sanders. “He will be a more effective leader for our movement if he remains in contention throughout the process.”
Former President Barack Obama, who is close to Mr. Biden, has grown increasingly anxious over the difficulties of incorporating the Sanders wing of the party into the Biden coalition, according to former aides and associates. But he has made it clear he will wait for the Vermont senator to approach him before playing a larger role, one former aide said.
One of the most conspicuous Sanders boosters on Wednesday was Mr. Trump himself, who has regularly claimed that the Democratic establishment was trying to rig the system against Mr. Sanders — and whose campaign viewed Mr. Sanders as its preferred opponent.
“The DNC will have gotten their fondest wish and defeated Bernie Sanders, far ahead of schedule,” Mr. Trump wrote on Twitter. “Now they are doing everything possible to be nice to him in order to keep his supporters.”
Officials close to Mr. Biden say they are sensitive to being perceived as pushing Mr. Sanders too hard. In a series of staff and surrogate calls over the past week, Biden aides have increasingly pressed for an approach in which Mr. Biden begins to ignore Mr. Sanders altogether and instead tries to turn the race into a two-man contest with Mr. Trump, according to people familiar with the campaign’s strategy.
Mr. Biden’s campaign also understands it is operating from a position of strength. On Wednesday it sent a memo to reporters that declared he had an “increasingly clear” path to the nomination and saying the 2020 primary race “is nowhere near as close as the 2008 and 2016 Democratic primaries.”
The two campaigns have been communicating, however. Kate Bedingfield, a deputy campaign manager for Mr. Biden, said in a statement on Wednesday that “since last week, the Biden and Sanders campaigns have been in regular contact at a senior level to discuss how the coronavirus is affecting the campaigns, how to adjust schedules and activities in light of that — as well as to discuss both Vice President Biden’s and Senator Sanders’s ideas on policy responses to the virus.”
“While the two campaigns obviously have their differences,” she added, “they are working together to try to promote the health and safety of their teams, those who interact with the campaigns, and the American people.”
Advisers to Mr. Sanders have begun to make peace with the fact that he will in all likelihood lose the nomination to Mr. Biden. But they also see no real downside in sticking it out, pointing to the uncertainty surrounding the primaries because of the coronavirus.
Mr. Sanders also views the crisis as a moment when the progressive agenda he has championed for years is especially vital, and he is eager to leverage his influence at a time when issues like health care and economic inequity are so resonant, some allies say.
On Tuesday night before most polls closed, he released a list of proposals to deal with the crisis, including that Medicare cover all medical bills and that $2,000 cash payments be provided to every American each month. He has indicated he plans to speak with Democratic leadership about the plans he has proposed.
And one aide said there had been regular discussions in the last several days about ways the campaign can help working families who may be stuck at home, including putting together programming for children to occupy them during the day.
After years of being excluded from what he sees as the party’s establishment clique, Mr. Sanders is also still determined to show that he is a superior candidate to Mr. Biden, whom he views as the establishment’s choice, some close to him say.
On the debate stage on Sunday, he delivered pointed attacks on Mr. Biden’s record in a way that vexed Biden supporters and left some Democrats wondering aloud if he might weaken the presumptive nominee in the general election against Mr. Trump.
Mr. Sanders, however, has insisted he thinks Mr. Biden can beat Mr. Trump, and none of his aides have indicated they are worried that staying in the race will divide the party in a way that benefits Mr. Trump.
Faiz Shakir, Mr. Sanders’s campaign manager, suggested Wednesday that a decision on how the senator would proceed was not imminent.
“The next primary contest is at least three weeks away,” Mr. Shakir said in a statement. “Senator Sanders is going to be having conversations with supporters to assess his campaign. In the immediate term, however, he is focused on the government response to the coronavirus outbreak and ensuring that we take care of working people and the most vulnerable.”
The ultimate decision on how to proceed, aides said, rests with Mr. Sanders and his wife, Jane, who were expected to return to Vermont on Wednesday night; his top campaign advisers were not scheduled to travel with him.
But discussions in recent days with more than 40 Democratic National Committee members and members of Congress found a clear majority believed he should get out of the presidential race now — with some warning that staying in could damage the progressive coalition he has built since 2015.
It is possible Mr. Sanders could stay in the race and run what effectively amounts to an inactive campaign as he focuses on his legislative agenda around the coronavirus.
Larry Cohen, a longtime Sanders confidant who is chairman of Our Revolution, the political organization that spun out of the 2016 Sanders campaign, said it was not in Mr. Sanders’s nature to drop out before all the primaries are over, “but the pandemic and the current delegate count could lead to a different outcome.”
“The delegate count,” he said, “speaks for itself.”