Mike Segar / Reuters

For the first 65 minutes of Thursday night’s Democratic debate in Miami, Joe Biden was standing at the catbird dais. The former vice president was enjoying his status as the front-runner. When he spoke, he speechified as though the others were just onstage coincidentally, not rivals for the nomination. And when Representative Eric Swalwell called on him to “pass the torch,” Biden just grinned and replied, “I’m still holding onto that torch.”

Senator Kamala Harris had other ideas. As the white men onstage around her sparred over police violence—with Swalwell making a daring attack on Mayor Pete Buttigieg—Harris broke in, as she had several times earlier in the night, and asserted her right to be heard.

“As the only black person onstage, I would like to speak on the issue of race,” she said to applause. Then she turned and took a dagger to Biden, invoking his recent baffling anecdote about working with the segregationist Senator James Eastland:

I do not believe you are a racist, and I agree with you when you commit yourself to the importance of finding common ground, but I also believe—and it’s personal, and I was actually very—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. And it was not only that, but you also worked with them to oppose busing. 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. And that little girl was me. So I will tell you that on this subject, it cannot be an intellectual debate among Democrats. We have to take it seriously. We have to act swiftly.

This was no spontaneous attack—Harris had clearly planned the ambush, and it worked. Biden was defensive. “It’s a mischaracterization of my position across the board. I do not praise racists. That is not true,” he said, rebutting an attack that Harris had not made. What was to come was even shakier. Biden meandered through a confusing response, invoking his career as a public defender in Wilmington, Delaware; riots in that city after Martin Luther King Jr.’s assassination; and his work as Barack Obama’s vice president, without spelling out what this added up to. Harris was unimpressed. “Do you agree today that you were wrong to oppose busing in America then?” she asked.

Biden insisted that wasn’t his position. Harris was still able to be bused to schools in Berkeley, he said, because the local government made that choice. “What I opposed is busing ordered by the Department of Education,” he said.

This is a thin defense, as Biden must have known. Throughout the civil-rights movement, southern governments raised the banner of local control in their fight against civil rights. The federal government ought not to force measures such as busing or integration itself, they argued. The fact that Biden’s stand against federally mandated busing was a political winner is a reminder that Delaware is south of the Mason-Dixon line, geographically and at times politically. But as Harris was quick to point out, only Washington had the muscle to step in and force the hand of local governments using local control as a smokescreen to maintain discrimination.

“There was a failure of states to integrate public schools in America,” Harris said, noting that even schools in the famously liberal Berkeley were barely integrated two decades after Brown v. Board of Education. “So that’s where the federal government must step in. That’s why we have the Voting Rights Act and the Civil Rights Act. That’s why we need to pass the Equality Act; that’s why we need to the pass the ERA. Because there are moments in history where states fail to preserve the civil rights of all people.”

Biden was by now on his heels, sputtering about old votes.

“I supported the ERA from the very beginning. I am the guy who extended the Voting Rights Act for 25 years and got to the place where we got 98 out of 98 votes in the United States Senate doing it. And I also argued very strongly that we in fact deal with the notion of denying people access to the ballot box,” he said.

Biden’s long record is a double-edged sword: He can point to votes for the Equal Rights Amendment when it was a hot-button issue the first time around, but he also served alongside men such as Eastland and Strom Thurmond, and his dredging up of this history cuts both ways.

Finally, he finished, sounding petulant: “Anyway, my time is up. I’m sorry.”

The potential double entendre, applying to both his answer on the debate stage and his command of the Democratic race, was not lost on anyone who heard it.

Whether it will become fact remains to be seen. Biden’s political death has been foretold many times. Gaffes have sunk Biden during previous presidential bids, but so far nothing in this campaign has been fatal. Even after the Eastland gaffe, African American Democrats of the older generation hastened to shore him up, and his formidable support among black voters doesn’t seem to have diminished significantly.

Moreover, busing isn’t all that popular. It hasn’t been a subject of much recent polling, but past polling shows that most voters want integrated schools but oppose busing to get them—a classic instance of voters supporting something in theory but getting hesitant when it’s their children who might have to ride a bus every morning. But the general population and the Democratic primary electorate are different groups with different views, not least on racial justice.

If Biden survives even this exquisitely designed, perfectly executed frontal assault from Harris, it’s reasonable to wonder if anything might knock him out of his lead in the Democratic race. But this is dangerous territory for Biden, and the incoherent rebuttals and peevish tone will not serve him well. Whether his time is really up remains to be seen, but if he fails to win the nomination, Thursday night’s debate will be remembered as the moment the final countdown began.

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