Even some of his own allies were admitting that Mr. Biden would likely be the party’s nominee.
“Tonight is a really good night for Joe Biden, and it looks like he will be the presumptive nominee,” Alexandra Rojas, the executive director of the progressive group Justice Democrats, said on CNN on Tuesday night. But she suggested that forcing Mr. Sanders to drop out would “shame” his supporters and deprive them of their ability to vote for their preferred candidate.
Officials close to Mr. Biden say they are keenly sensitive to not being perceived as pushing Mr. Sanders too hard — although that is what many of them want to do. In a series of staff and surrogate calls over the past week, Biden aides have emphasized that point and increasingly pushed for an approach in which Mr. Biden begins to ignore Mr. Sanders altogether and instead tries to turn the race into a binary contest between himself and Mr. Trump, according to people familiar with the campaign’s strategy.
And 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 speaks for itself,” he said.
Already, public health concerns have prevented Mr. Sanders from holding his signature rallies and relegated his supporters to phone banking rather than canvassing in person door-to-door. And on Tuesday morning, his top spokesman, Mike Casca, said in a statement that the campaign was not conducting “get out the vote” outreach and was instead “making clear to voters that we believe going to the polls amid the coronavirus outbreak is a personal decision.”
Ohio, Georgia, Louisiana, Kentucky and Maryland have postponed their primaries, and more states could follow, raising the possibility that a significant portion of the election season could stretch well into June.
It is possible Mr. Sanders could stay in the race to collect delegates in order to accumulate leverage and bolster progressive power in party reform — while running what effectively amounts to an inactive campaign as he focuses on his legislative agenda around the coronavirus.
So far Mr. Sanders has not yet been abandoned by a critical mass of his supporters. Robert Reich, the former labor secretary, said Monday that the time had come for Mr. Sanders to concede the nomination to Mr. Biden, but few other Sanders supporters have done so — even while they acknowledge his motivation may be something different from winning the party’s nomination.