A day after an electric Democratic debate, several candidates attempted to turn Joe Biden’s decades-long opposition to federally mandated school busing into a broader indictment of his commitment to racial integration, moves that showed the presidential contest has entered a more confrontational phase.

After Biden was criticized from all corners of the debate stage Thursday — on his age, record and ideology, and most dramatically over busing and his relationships with segregationist senators — candidates began shifting their strategies to dive into a more ample conversation about race. The field’s two black candidates on Friday amplified their criticism of Biden, whose eight-year partnership with the country’s first African American president has given him strong support among black voters that Sens. Kamala D. Harris (Calif.) and Cory Booker (N.J.) are seeking to dislodge.

Biden scrambled to stem the fallout, launching a defense of his performance during an event in Chicago and sending emails to supporters, but there were some indications that several rocky weeks had taken a toll. A top fundraiser who had helped recruit donors for a San Francisco fundraiser said he would not attend, while another said Biden’s performance could reverberate through the universe of unaligned donors.

It also exposed one of his biggest challenges: trying to run a forward-looking campaign without getting mired in the positions held in a 44-year career. And it dimmed some of the aura of inevitability around Biden’s campaign, illustrating how the most experienced debater in the field could be knocked off stride with an attack on a long-held part of his record.

During the most prominent exchange in four hours of debates that took place over two nights, Harris on Thursday said Biden was wrong to oppose busing in his home state of Delaware in the 1970s.

On Friday morning, she and Booker broadened their critique of Biden to say his deference to states on busing issues was a sign not only of his stance on that divisive topic but how he felt about broader federal intervention to stem racial bias.

I was actually a bit surprised to hear how he described, in defense of his position, his perspective on the role of the federal government, and in particular, he mentioned the Department of Education,” Harris said on MSNBC. “We have so many examples in history where states have limited or restricted people’s civil rights. . . . We have certain values that are national standards, and we’re not going to let states compromise that.”

On Thursday, Harris had framed her criticism of Biden in emotional and personal terms.

“And, you know, there was a little girl in California who was part of the second class to integrate her public schools, and she was bused to school every day,” Harris said. “And that little girl was me.”

On Friday afternoon, Biden began a speech to the Rev. Jesse Jackson’s civil rights organization in Chicago by both praising and rebuking Harris.

“I heard and I listened to and I respect Senator Harris,” Biden said. “But we all know that 30 seconds to 60 seconds on a campaign debate exchange can’t do justice to a lifetime committed to civil rights.”


Democratic presidential candidates wave as they enter the stage for the second night of the Democratic primary debate hosted by NBC News in Miami. (Wilfredo Lee/AP)

Biden told the majority black audience that he has “fought my heart out” on issues of racial equality. He said he never opposed voluntary busing, but statements he made in the 1970s illustrated how strongly he opposed any federally mandated or court-ordered busing.

“I oppose busing. It’s an asinine concept, the utility of which has never been proven to me,” he said in a 1975 interview. “I’ve gotten to the point where I think our only recourse to eliminate busing may be a constitutional amendment.”

Booker, who watched the second round of the debate on television after participating in Wednesday’s first round, expressed shock Friday at Biden’s attempt to differentiate between state and federal rights when it came to busing.

“I think that anybody that knows our painful history knows that on voting rights, on civil rights, on the protections from hate crimes, African Americans and many other groups in this country have had to turn to the federal government to intervene because there were states that were violating those rights,” Booker said on CNN.

Booker also praised several former presidents, including John F. Kennedy and Lyndon B. Johnson, for “having the courage to bring the federal government in to stop states from sanctioning the kinds of bigotry and bias that was so hurting African American communities.”

Fallout from the first debate, meantime, hit upon multiple candidates Friday. As she attempted to harness momentum, Harris was forced to again clarify her views on health care, saying she does not support abolishing private health insurance despite having raised her hand when candidates were asked if they would do so in favor of a government plan.

Harris said she misinterpreted the question, thinking moderator Lester Holt was asking whether she personally would be willing to use a government plan instead of a private one. Earlier this year she had to clean up similar confusion stemming from her dismissal of the need for private insurance during a CNN town hall.

Republicans seized on Harris’s switch on social media, where Republican National Committee Chairwoman Ronna McDaniel called Harris “a liar.” Donald Trump Jr. retweeted that and other messages casting Harris as a flip-flopper and criticizing her record as a prosecutor.

Harris had drawn similar attention during her Senate interrogation of Republican nominees, with President Trump saying she had “a nasty wit.” Her performance Thursday unleashed a far more substantial onslaught from Republican opposition, the kind previously reserved for Biden and Sens. Bernie Sanders (I-Vt.) and Elizabeth Warren (D-Mass.) — who have consistently polled ahead of her.

While much of the post-debate intensity centered on Biden, other candidates sought to build off their performances and find new foils. Sanders released a statement aimed at Harris and others in the field unwilling to commit to ending private insurance.

“Let us all be very clear about this: If you support Medicare-for-all, you have to be willing to end the greed of the health insurance and pharmaceutical industry,” Sanders said.

Julián Castro, the former San Antonio mayor and housing secretary, tried to build off his bounce from Wednesday night’s debate, where he attempted to establish himself as a leader on immigration by sharply criticizing former congressman Beto O’Rourke of Texas.

Castro’s campaign announced that the day after he took the stage was the single best fundraising day of his campaign, and it will be followed by an expansion of his staff and facilities. Castro plans to open an office this weekend in San Antonio; his staff had been working out of shared corporate space for months.

Biden was not the only candidate confronting fresh questions about race. On Thursday night, South Bend, Ind., Mayor Pete Buttigieg was asked about the shooting of a black man by a white officer in South Bend, and tried to assume responsibility for the lack of diversity on the police force there.

“I couldn’t get it done,” said Buttigieg, admitting that his attempts to bring more African American officers to the force had failed.

Buttigieg took a few blows on the issue from his fellow candidates, most notably Rep.Eric Swalwell (Calif.), but his performance was not entirely consumed by the issue — even as it did require him to address it.

Then, Friday morning, fresh questions about his feel for sensitive racial issues emerged after his visit to the Homestead Migrant Detention Facility outside Miami. Buttigieg was one of several candidates to visit the facility over the past three days, but received unique pushback from protesters there who noted he did not climb the ladders they set up so visitors could see over the walls of the facility to check the condition of children detained there.

BuzzFeed reported that protesters expressed frustration with Buttigieg as he drove away without climbing that ladder, as others had done — particularly since he had made time for a television interview.

The two-day Democratic debate, as the highest profile campaign event yet in a race whose giant field has befuddled voters, posed both possibility and threat for the candidates. In its aftermath, Biden’s camp took particular pains to try to settle down nervous supporters.

Rep. Cedric L. Richmond (D-La.), a co-chairman of Biden’s campaign, said he wasn’t certain about the entirety of Biden’s position on busing. But he suggested that it should not be a problem because voters should prioritize his partnership with President Barack Obama.

“All of that was out there when the first African American president of the United States decided to pick Joe Biden as his running mate, and he had the vice president’s back every day of a week,” Richmond said. “So I’m not sure that voters are going back 40 years to a nuanced conversation to decide.”

“If you want to put Vice President Biden’s record on civil rights beside anybody else, I think he’ll stand the test of time,” said Symone Sanders, a top Biden adviser who, like Richmond, is African American.

Stan Greenberg, a Democratic pollster who conducted focus groups during the debate, said Harris saw a 20 point bump in favorability, showing that her attacks were resonating. But it wasn’t necessarily coming at Biden’s expense. His numbers, Greenberg found, increased by 6 points.

“Even though he was attacked by not only the senator but also by other people on the stage, his favorability rating went up,” Greenberg said.

Greenberg said Biden’s support increased even more among African American voters, shooting up by 18 percentage points after he was on the debate stage; Harris’s numbers among black voters went up 30 points.

“What the vice president represents is the Obama legacy that’s under attack,’ ” Greenberg said. “Carrying on the attack has a complicated effect.”

Some signs of trouble were more evident: Dana Perlman, a Los Angeles attorney and Obama fundraiser, said Biden’s performance might affect unaligned donors.

“There were some people who were waiting, and they might be interested in other candidates,” Perlman said.

Tom McInerney, a San Francisco lawyer and a former Obama fundraiser, said Biden’s performance confirmed his decision in recent weeks to pull back from raising money for the former vice president.

McInerney had recruited donors to attend Biden’s fundraising events in San Francisco this weekend, designed to raise campaign cash before Sunday’s second-quarter fundraising deadline. But McInerney has told Biden’s campaign he is stepping back to assess whether he can fully support Biden again.

“I was hoping to see a strong debate performance, thoughtful positions and comments, and see how he holds up under the campaign, because the campaign is very difficult and rigorous,” McInerney said. “I’m just concerned about whether or not he actually thought through this.”

Michelle Ye Hee Lee, John Wagner, Annie Linskey and Scott Clement contributed to this report.