The newly announced lineup for the second Democrat presidential debate sets up a showdown between former Vice President Joe Biden, the purported frontrunner, and Sen. Kamala Harris (D-CA).

On Thursday, a panel of CNN hosts picked the lineup for the second debate to be held on July 30-31 in Detroit, Michigan. Biden initially lucked out by not having to debate Sen. Elizabeth Warren (D-MA), whom most polls have shown within striking distance of the frontrunner, but that came at the price of having to face off against Harris again.

At the debate last month, Harris surprised many by confronting the former vice president over his praise for two segregationist Democrats, the late-Sens. James Eastland (D-MS) and Herman Talmadge (D-GA). Biden had invoked the two men, who dedicated their careers to halting the progress of civil rights, during a fundraiser in New York City while touting his ability to forge “consensus” in Congress.

“I agree with you when you commit yourself to the importance of finding common ground,” Harris said, “but I also believe…it was hurtful to hear you talk about the reputations of two United States senators who built their reputations and career on the segregation of race in this country.”

Harris was quick to point out at the debate that both Talmadge and Eastland were allies in his campaign against busing to integrate public schools — something which Biden had refrained from mentioning.

“It was not only that, but you also worked with them to oppose busing,” she said. “There was a little girl in California who was part of the second class to integrate her public schools and she was bussed to school every day. That little girl was me. So I will tell you that on this subject, it cannot be an intellectual debate… we have to take it seriously.”

The rebuke left Biden reeling to respond. The former vice president tried to claim Harris had mischaracterized his record, but was unable to offer proof. Instead, he only muddled his position on busing and inaccurately claimed to have never praised racists in the first place.

As soon as CNN announced the lineup on Thursday, more than a few individuals, including fellow presidential candidate Andrew Yang, noted the opportunity for a rematch between Biden and Harris.

Glad I’m not standing in-between Joe and Kamala. — Andrew Yang (@AndrewYang) July 19, 2019

The showdown is likely both attractive and dangerous for the candidates. Since the debate, Harris’s polling numbers have steadily increased,vaulting her into the top rung of competitors. The senator, however, has been unable to overtake Biden, who, despite having dropped in the polls, still leads the pack. A rematch gives Harris the chance to solidify her standing in the field and potentially set her up to replace Biden as the establishment candidate should he falter.

The situation is slightly different for Biden. Although the former vice president has seen polling numbers drop, the more pertinent question is if he can explain his more than 40-year record on busing in a manner that doesn’t jeopardize his standing with black voters. To date, the frontrunner has struggled to do so.

There are also renewed concerns about his capabilities as a candidate and not just from opponents. After the debate, Biden’s team was reportedly “freaking out” about his handling of Harris and overall poor performance compared to the other candidates. Federal Election Commission filings released this week show Biden’s campaign took the encounter with Harris and the overall performance seriously enough to have hired a speech coach, best known for his work with President Bill Clinton, one day after the debate.

Complicating matters is that relationships between Harris and Biden have only frayed since the confrontation. In an interview with CNN shortly after the debate, the former vice president and his wife expressed astonishment at the ferociousness of Harris’s attacks.

“I’ve been surprised, not about the attacks, but I’ve been surprised at the intentions sometimes of the attacks, coming from people who know me,” Biden said.

Although the former vice president has refrained from attacking Harris personall, the same cannot be said of his mostly-male surrogates, who have sought to paint the California senator as overly ambitious.

“It’s not right, it’s distressing. It shows a lack of integrity: win at any cost,” Dick Harpootlian, the Biden’s campaign lead in South Carolina, told Politico when discussing the issue.”Why is she taking that shot when Joe Biden and his son did everything they could to help her? It was more of a comment about her than it was about Joe Biden.”

Harris and her campaign, for their part, have refused to be intimidated by Biden or his wide network of supporters. Just last week, the California Democrat said she could not stand on a debate stage where candidates were vying to “be the next president of the United States” and allow individuals “to engage in revisionist history.”

“We cannot rewrite history on this, and that was part of the reason I raised it on that stage,” Harris told The Breakfast Club, a New York-based radio program. “America’s history on this issue is that there had to be busing because there were people like those segregationists … who were using every breath they had to fight against integration of the public schools of America.”

“I can’t stand on that stage and allow certain conversations to be taking place,” she added.