WESTERVILLE, Ohio — She had bobbed and weaved her way through an onslaught of attacks, but near the end of Tuesday’s presidential debate, Senator Elizabeth Warren did something unusual: She paused.
She was talking up the Consumer Financial Protection Bureau she helped create, saying it was included in financial reform legislation despite the objections of Republicans and even “some of the Democrats,” when former vice president Joe Biden cut in over moderator Anderson Cooper.
“I went on the floor and got you votes, I got votes for that bill, I convinced people to vote for it,” Biden said, his voice rising and his flattened hand sweeping through the air.
When Cooper asked for Warren’s response, she took half a breath. And then another. Seconds went by.
“I am deeply grateful — to President Obama, who fought so hard to get that agency passed into law,” Warren said, purposely withholding her thanks from an opponent with whom she has long tangled over consumer issues.
Warren has studiously avoided wading into conflict with her main rivals as her presidential campaign has gathered steam in recent months, but by Tuesday’s presidential debate, that was impossible. Her exchange with Biden was the tensest in a long evening that cast Warren in a new role, at least in the eyes of her Democratic opponents: A front-runner, and the one to beat in a primary field newly flush with uncertainty.
One by one, Warren’s rivals laid out her potential weaknesses in front of an electorate desperate to defeat President Trump, at times displaying a new willingness to question personal attributes like honesty or demeanor. To Beto O’Rourke, she was “punitive.” Biden called her “vague.” To Pete Buttigieg, she had a one-track mind — for “infinite partisan combat.”
In a preview of how she would seek to shape the race if she remains atop the field, Warren responded dexterously but rarely in personal terms, seeking instead to contrast the sweeping change she has promised with what she suggested is a lack of ambition from her rivals.
“I understand that this is hard, but I think as Democrats we are going to succeed when we dream big and fight hard, not when we dream small and quit before we get started,” Warren said, leaning on her campaign slogan instead of a totally fresh response.
In the three previous debates, many of the contenders on the crowded stage were more interested in trying to deflate Biden, but two factors have changed that. President Trump has been relentlessly attacking Biden over his son Hunter’s business activities in Ukraine, a line of criticism no Democrat seems eager to reinforce. And Warren has tied or overtaken Biden in several national and early state polls.
So for much of the three-hour debate, lower-polling candidates eagerly auditioned for the role of chief Warren foil, with Biden at times seeming to disappear from the stage. Vermont Senator Bernie Sanders, making a strong first appearance at a major campaign event since he had a heart attack on Oct. 1, also eluded much of the crossfire, although he faced pointed questions from the moderators about his health.
The offensive on Warren began with Medicare for All, the single-payer government health insurance system she and Sanders have embraced. Moderator Marc Lacey, the national editor of the New York Times, pressed Warren on her refusal to acknowledge that middle-class taxes would go up to pay for it, but she said simply that she would not sign a bill into law that doesn’t lower overall costs for those families.
“We heard it tonight, a yes or no question that didn’t get a yes or no answer,” said Buttigieg, the mayor of South Bend, Ind., before touting his own more limited plan, “Medicare for all who want it.” He added: “Your signature, senator, is to have a plan for everything, except this.”
Warren, apparently as committed as ever to not proffer a soundbite on her willingness to raise certain taxes, dismissed Buttigieg’s plan as unaffordable while also labeling it as “Medicare for all who can afford it.” But, in a sign of how her refusal to expound on funding for Medicare for All has opened her up to criticism from the left and the right, Sanders took a gentle swipe, too:
“I do think it’s appropriate to acknowledge taxes will go up,” he said.
Then Amy Klobuchar, the Minnesota senator who has been stubbornly stuck near the bottom of the polls, piled on. “At least Bernie’s being honest here,” she said, before criticizing Warren’s ideas as unrealistic.
“The difference between a plan and a pipe dream,” Klobuchar said, “is something you can actually get done.”
Jabs like that were always inevitable for a candidate seeking to fundamentally restructure the American economy, and they may come as a relief to moderate voters worried about the party’s leftward drift.
But the debate also revealed the perils of attacking a candidate who has built her political brand on populism. At one point, Warren offered a rejoinder to opponents who have not embraced a wealth tax, as she and Sanders have:
“Does everyone else on this stage think it is more important to protect billionaires than it is to invest in an entire generation of Americans?” she asked.
Soon, O’Rourke suggested that Warren, who has made the idea of taking on hard fights central to her political brand, could be too divisive to win a general election.
“Senator Warren is more focused on being punitive and pitting some part of the country against the other instead of lifting people up,” said O’Rourke, the former Texas representative.
“I’m really shocked at the notion that anyone thinks I’m punitive,” Warren said, explaining she simply wanted the wealthy to pay for public goods that helped them — a reprise of a line she used in her 2012 Massachusetts Senate campaign.
Some attacks on Warren did not seem to land. California Senator Kamala Harris, who faded to the background for much of the debate, tried to knock Warren for not signing on to her calls to have Trump banned from Twitter. Warren tried to steer the spotlight instead toward Democrats — like Harris — who court wealthy donors to fund their campaigns, a practice Warren has sworn off.
Not every onstage attack was reserved for Warren. O’Rourke and Buttigieg sparred over the Texan’s proposal for a mandatory buyback of assault weapons and Sanders punctured Biden’s boast that he had accomplished the most of anyone onstage.
“You got the disastrous war in Iraq done. You got a bankruptcy bill, which is hurting middle-class families all over this country. You got trade agreements, like NAFTA and PNTR, with China done, which have cost us 4 million jobs,” Sanders said.
That’s when Warren brought up the Consumer Financial Protection Bureau, showing a new willingness to engage more directly with her chief competitor for the race’s top slot.
As she sought to cast the creation of the bureau as a worthy fight that some Democrats had tried to stop, Biden interrupted her.
“You did a hell of a job in your job,” he said, prompting the unflappable Warren to show a rare flash of annoyance.
“Thank you,” she said, lightly, and continued to speak.
Laura Krantz of the Globe staff contributed to this report. Jess Bidgood can be reached at Jess.Bidgood@globe.com. Follow her on Twitter@jessbidgood