DERRY, N.H. — Since he got in the 2020 presidential race, Joe Biden and his supporters have cloaked the former vice president in the mantle of electability, arguing that his appeal to Black voters and disaffected Rust Belt Democrats alike uniquely positioned him to defeat President Trump.

That image, which had withstood weak debate performances and other gaffes, started showing foundational cracks this week with his subpar showing in the Iowa caucuses. Biden responded by ripping into two of his top rivals on the trail Wednesday, including Senator Bernie Sanders of Vermont, who continues to lead the former vice president in polls of likely Democratic primary voters in New Hampshire.


Like any good underdog, Biden got scrappy.

Speaking at a VFW hall, Biden warned that a Sanders nomination would hurt Democrats across the country, given the Vermonter’s willing embrace of the label “socialist.” A string of polls show Sanders beating Biden in New Hampshire, including the latest Boston Globe/WBZ-TV/Suffolk University daily tracking poll of likely Democratic primary voters.

"If Senator Sanders is the nominee for the party, every Democrat in America up and down the ballot; blue states, red states, purple states, in easy districts and competitive ones, every Democrat will have to carry the label Senator Sanders has chosen for himself,” Biden said at the get-out-the-vote event in Somersworth, N.H. “I don’t criticize him. He calls himself a democratic socialist.”

As for former South Bend, Ind., mayor Pete Buttigieg, who is currently leading in the incomplete Iowa results, Biden hit the 38-year-old military veteran, too. The charges: Buttigieg’s relative lack of experience and his criticism of the Obama administration.

"I have great respect for Mayor Pete in his service to this nation, but I do believe it’s a risk, to be just straight up with you, for this party to nominate someone who has never held an office higher than a mayor of a town of 100,000 people in Indiana. I do believe it’s a risk,” the former vice president said.


His comments amounted to a reframing moment for the 78-year-old who has unsuccessfully run for president twice before. No longer the presumptive nominee, Biden spoke of himself as the soon-to-be comeback story. He called his disappointing performance in Iowa “a gut punch” then added that "this isn’t the first time in my life I’ve been knocked down.”

As Biden launched the fresh attacks on Sanders and Buttigieg, a top campaign aide tried to cast doubt on the partial results from Monday night’s Iowa caucuses that show Biden finishing an embarrassing fourth behind Buttigieg, Sanders, and Senator Elizabeth Warren of Massachusetts.

During a contentious CNN interview Wednesday, senior Biden adviser Symone Sanders refused to say whether she thought the results were correct or not, after pointing to problems with an app used to tabulate precinct results.

“I guess we’ll have to take the Iowa Democratic Party at their word,” Sanders eventually said, after CNN anchor Brianna Keilar pressed her repeatedly for an answer.

Buttigieg, who saw his support jump in Wednesday’s Boston Globe tracking poll, held only a single event in New Hampshire Wednesday, opting to travel to New York for a trio of fundraisers Wednesday and Thursday.

He focused on the issues -- not political strategies -- at a student forum on climate change in downtown Concord, pitching a unity message on an issue that animates young voters, a cohort he has struggled to attract.


“If everybody is vulnerable to climate harms, everybody can participate in the solution,” said Buttigieg, 38, the youngest candidate in the Democratic presidential race.

“This is too big, too important, too existential to be another partisan tug of war.”

Exuding confidence, Sanders didn’t mention any of his Democratic competitors during an event in at a historic opera house in Derry. Instead, he trained his fire on Trump, who he called “the most dangerous president in the modern history of our country.”

He somberly noted he would be flying to Washington after the event to vote to remove Trump from office.

Sanders also didn’t acknowledge that Buttigieg was ahead of him in the Iowa delegate count. He focused on his lead in the popular vote, and joked that “I assume that one of these years, that vote count will be completed.”

While he didn’t mention Biden, Sanders offered a rebuttal to the former vice president’s claims that Sanders faces longer odds in defeating Trump.

“To defeat Trump, who will be a very formidable opponent . . . we are going to have to have in November the largest voter turnout in the history of this country,” Sanders told the enthusiastic crowd. "Old fashioned status quo politics is not going to generate the kind of energy and excitement we need to bring working class people into the political process, to bring young people into the political process, to grow the base.”


Sanders skeptics this week have begun pointing to a potentially large flaw in that argument, regarding his electability: The Vermont Democrat did not, in fact, inspire a surge in new people coming out to caucus. Participation rates tracked below what many pundits predicted, on par with turnout from four years ago and short of the record-high numbers in 2008.

But the stakes in New Hampshire appear to be a much higher for Biden. Democratic strategists said another disappointing performance could further wound his candidacy, and cause his lead in South Carolina, which his campaign considers a key firewall, to falter.

“If you’re the guy who’s going to win, you’ve got to win," said Mary Anne Marsh, a Boston-based Democratic strategist.

Patti Solis Doyle, Hillary Clinton’s 2008 campaign manager, compared Biden’s situation to Clinton, who turned things around in New Hampshire that year after coming in third in Iowa.

“She did a slew of events, stayed until absolutely the last question was answered and took it to her opponents,” Solis Doyle said.

"If he (Biden) wants to get the frontrunner status back he’s got to leave it all on the field in New Hampshire,” she said.

Warren wasn’t the focus of the day, but she faced her own round of tough questions Wednesday, forced to explain her campaign’s decision to cancel a flight of ads that had been scheduled to air in South Carolina and Nevada later this month.


“It’s about the fact that we completely financed our campaign through the grassroots, and I just want to be careful about how we spend our money,” Warren said.

The cancellation, first reported by Advertising Analytics, could raise questions about her finances — and whether Warren will be able to compete in as many states as she wants to if she does not notch an early primary win to boost her momentum and juice her fundraising.

She has an expansive ground game, with more than 1,000 campaign staff in 31 states — a costly model with a huge payroll that she is hoping will pay off later in the primary calendar.

Warren had $13.7 million in cash on hand at the end of last year; more than Biden, who had about $9 million left, but less than Buttigieg’s $14.5 million and Sanders’ $18.2 million. Warren, Buttigieg and Sanders all spent more than they raised in the last three months of the year.

Warren said she she is “fighting for every vote” in New Hampshire, but has built an operation “for the long haul.”

Liz Goodwin, Jess Bidgood, and Laura Krantz of the Globe staff contributed to this story.

Victoria McGrane can be reached at victoria.mcgrane@globe.com. Follow her on Twitter @vgmac.