Over the past few days, two of the leading male candidates in the Democratic presidential primary race — Joe Biden and Pete Buttigieg — have escalated separate lines of attack as they attempt to counter the field’s most prominent woman: Sen. Elizabeth Warren (D-Mass.) is antagonistic and angry.

She also is an uncompromising elitist, they argue, suggesting that if she were the nominee, it would harm the party in the must-win states in the upper Midwest.

The new attacks, marking a more vigorous phase of the race, get at something far beyond her policy positions, and into one of the most fraught areas for a female candidate: Is she likable?

Pushing that argument is treacherous given that many Democrats remain upset over what they view as sexist treatment of Hillary Clinton, the party’s last nominee. Warren’s allies view the language being used against her as constructed to be particularly devastating for female candidate and beyond the policy divisions between her and her rivals.

Women’s activism — driven in part by Clinton’s loss — has fueled social and political movements, evident in the #MeToo campaign and in election results during the 2018 midterms and on Tuesday night. But it also comes as Democrats worry about turning off voters — many of them white, working class, and male — in states such as Pennsylvania, Michigan and Wisconsin.

Buttigieg laid the groundwork by criticizing Warren’s “my way or the highway approach” and suggesting recently that she is “so absorbed in the fighting that it is as though fighting were the purpose.” Biden, launching a range of new attacks on Warren, said this week that she reflects “an angry unyielding viewpoint that has crept into our politics.”

“Labeling a woman angry, or emotional or shrill, is a well-worn strategy when it comes to attacking women’s qualification to serve an office,” said Amanda Hunter, a spokeswoman for the Barbara Lee Foundation, which conducts research on women seeking elected office.

Those attacks, she said, can be effective because they sow doubt in the person and make them less likable.

“Voters will not support a woman they do not like even if they believe she’s qualified,” she said, citing extensive research. “But they will vote for a man they do not like.”

Branding Warren “angry” felt particularly off-key to those who have watched her closely. She often stands for hours in line to take photos with supporters, grinning thousands of times in a row. And while her rhetoric can turn hot — particularly when directed at banks and corporate interests — it comes across more as frustration at the problems she sees than anger.

“Nothing that she is doing seems to be telegraphing that she is angry,” Hunter said. “It seems that those attacks are really coming from somewhere else and are more premeditated and a way to play on her gender rather than a reaction to something that she’s actually doing.”

Warren’s campaign declined to comment.

“It’s the same old ugly caricatures of women who succeed in every industry,” said Rebecca Katz, a liberal political strategist who is unaligned but has donated to Warren and others. “Honestly, it was how Warren was dismissed early on. But then people got to know her. And really she is nothing like this ugly caricature. But you have two of the top Democrats trying to make her into something she’s not.”

“If we nominate a woman, Trump is going to go after her in very personal ways,” she added. “It is just surprising that it is happening from other Democrats.”

Biden supporters rejected any notion that his language had sexist undertones. They pointed to his record on women’s rights, and suggested that any outrage should be reserved for instances that are more overtly sexist.

“If I said those things about her it wouldn’t be called sexist,” said Carol Moseley Braun, a Biden supporter who was the first female U.S. senator from Illinois.

“Here’s someone who spent all these years fighting for the rights of women and now you turn him into some insensitive boor?” she added. “It’s crazy. That’s the circular firing squad.”

Biden’s campaign blamed Warren for the turn toward more personal attacks, pointing to her comments that he was “running in the wrong presidential primary.” She made the comment as the two disagreed over the details of her Medicare-for-all plan.

“Us asking for straight answers on health care escalated to Vice President Biden not having a place in the Democratic primary,” said Symone Sanders, a top Biden adviser. “That’s absurd. Let’s not attack one another. Let’s have a high-level policy debate.”

Biden’s campaign also pointed to previous instances of him referring to male candidates in similar ways, including a 2008 reference to Sen. John McCain (R-Ariz.) as “an angry man.”

“It is not sexism,” said Alyssa Milano, an actress and politically active Democrat who is co-hosting a Biden fundraiser and has also donated to Buttigieg. “We are having a substantive debate on our country’s future, and this was part of it.”

Buttigieg’s campaign also rejected the notion that his comments could viewed through a gender lens, saying he has used similar terms to describe Sanders’s approach to health care. The Buttigieg campaign further noted that Warren often embraces the label of a “fighter.” She often closes events with the refrain, “Dream big! Fight hard!”

“This is 100 percent a comment on the dysfunctional state of politics in Washington, where people seem to be more focused on fighting with each other than delivering results,” said Lis Smith, one of his top advisers. “And it’s a contrast he’s been driving with his Washington competitors since the day he got in this race. Any suggestion to the contrary is wrong.”

Warren has not to this point coalesced women around her candidacy. A recent national Washington Post-ABC News poll found 27 percent of female Democrats supported her, compared with 14 percent of men. Biden had support from 30 percent of men and 25 percent of women, according to the survey.

As she campaigns, she seems intent on deflecting any gender criticism. When she talks about her wealth tax, she makes a point of noting that it’s not intended to be punitive.

“I’m not proposing this because I’m cranky,” Warren said recently.

Warren often recounts how those in the Washington establishment advise her to curb her approach.

“ ‘They said, ‘The way to run is to talk in vague generalities. Smile more,’ ” Warren said, a line that elicits a laugh from the audience.

Clinton’s presidential campaign also faced criticism that focused on her gender — whether her laugh, her pantsuits, or her likability.

“Historically, calling a woman candidate angry or elitist could hurt her as it contributes to a sense that she is unlikable,” said Jennifer Palmieri, who was Clinton’s communications director and has advised presidential candidate and Montana Gov. Steve Bullock. “But Warren has impressed me with all she has done to inoculate herself from these kinds of attacks. She . . . is nothing but a hugging, selfie-loving, joyful campaigner out on the road. It’s hard to make angry or elitist stick to her.”