“As the only,” Senator Kamala Harris interjected during the second Democratic debate, in Miami, “as the only black person onstage, I would like to speak on the issue of race.” She directed her attention at Joe Biden. The former vice president’s record on civil rights—and his fond remembrances of segregationist senators—has recently faced a wave of scrutiny. He’s argued that his ability to work with those he disagrees with is a mark of civility, but the former prosecutor was prepared to challenge him. She wanted to address a particular part of his record.

“You also worked with them to oppose busing,” she said. “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.” Her team tweeted a photo of her when she was in school with the line “That little girl was me.”

There was a little girl in California who was bussed to school. That little girl was me. #DemDebate pic.twitter.com/XKm2xP1MDH — Kamala Harris (@KamalaHarris) June 28, 2019

Biden stood, staring into the applauding audience, before objecting that Harris had presented a “mischaracterization” of his position on race and busing. “What I opposed is busing ordered by the Department of Education,” he said. It wasn’t a defense that helped.

The confrontation captured an evolution—of the Democratic Party, of the country—that has taken place within Biden’s lifetime. Harris reminded viewers that this was all in her lifetime, too, and how different a tale. There the two were, staring at each other, their personal stories inextricably bound up in the bigger American story.

Biden tried to defend himself before relenting to the clock. “Anyway,” Biden said, “my time is up.” Indeed it was.