BERKELEY, Calif. >> In 1967, the superintendent of the Berkeley, California, school district had resolved to desegregate the city schools. “We will set an example for all the cities of America,” he wrote in a report called “Integration: A Plan for Berkeley,” which he presented to the Berkeley Board of Education. “The children of Berkeley will grow in a community where justice is part of their pattern of life,” the report stated.

Several years later, a young girl named Kamala Harris, the daughter of a Tamil Indian mother and a Jamaican father, boarded a school bus — part of that school integration program that would change her, the city and the country’s conversation about racial politics.

“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,” Harris, now a senator and candidate for president, said on Thursday evening onstage at the Democratic debate. She was directly addressing former Vice President Joe Biden, and what she described as his history of opposition to mandatory busing.

In that moment, Harris invoked a complex part of American history, and the way cities tried to address how segregated the country’s classrooms remained more than a decade after Brown v. Board of Education was decided. She also made plain how the conversation about integration that took place in Washington and in cities around the nation directly affected the life of a first-grader on a school bus. They played hand-clapping games to pass the time, a classmate remembered, aware that their bus ride took them to a neighborhood different from theirs, but not that it was something a superintendent had to fight for.

Students who attended Berkeley public schools during the early years of the integration effort recall the experience as a defining one for them.

“Racism didn’t go away because we were bused,” said Doris Alkebulan, 58, who was part of the initial group of black students in Berkeley to be bused to a majority white school. “What about play dates? Were you going to be invited to the birthday party? Would you be chosen for the team?” She remembered that kids would say, ‘Oh we can’t play with you’ and explain the reason with a racial slur.

“I didn’t even know I was black until then,” Alkebulan said.

Alkebulan said that the experience profoundly shaped her life and that it was emotional watching Harris call upon that history. “She got it right,” Alkebulan said.

If Biden represents a more moderate vision of the Democratic Party, Harris onstage at the debate reflected on a time in Berkeley history when moderate politics were falling apart. Though the city was a microcosm of seismic political changes in the country as a whole, including anti-war sentiment and free speech activism, one major catalyst for transformation was school busing. As white families who opposed busing left town for the suburbs in 1967, they gave way to an insurgent new left.

“Busing was really when Berkeley split and became leftist because a lot of people who couldn’t handle that change, they left,” said Jef Findley, a librarian at the Berkeley Public Library specializing in city history, who helped make an oral history of the city’s busing and desegregation. “The moderate, pro-business rightist town became a leftist town.”

Carole Porter, 55, who now works in information technology, lived around the corner from Harris. The two girls took the bus up the hill from the middle-class Berkeley flats where they lived to Thousand Oaks, a school in the more affluent white Berkeley hills. Porter recalled that the ride took about 40 minutes.

Harris attended a Montessori school for kindergarten and joined Porter at Thousand Oaks in first grade. On the debate stage, she described herself as “part of the second class to integrate her public schools,” and her classmates were the second group of kindergartners to be bused to schools outside their neighborhoods. A campaign spokeswoman confirmed that Harris joined the class in 1970, her first-grade year, which was the third year of integration. The school had been 2.5% black in 1963. In 1969, it was 40.2% black as a result of integration.

Porter, who has donated to Harris’ campaign, remembered her former classmate as a responsible student who was being raised by a single mother.

They played games like “Miss Mary Mack,” did cats cradle with yarn and discussed recess plans, Porter said. She remembered the neighborhood the two girls shared as a lower-middle class area full of working people.

“It was very diverse — we had a United Nations in our neighborhood,” Porter, who is black, said. “Busing gave us opportunities to leave our neighborhood and see affluence.”

Most Americans at the time were in favor of integration, but few thought busing was the best method, according to a 1973 Gallup poll. Given alternatives like low-income housing in middle-income areas or changed school boundaries, only 9% of blacks said they preferred busing, and just 5% of whites did.

Approval of busing largely broke along racial lines, though often opposition was framed around mandatory busing, or rules set at the national level, rather than on integration itself. Biden expressed a version of that view at the debate last week.

“I did not oppose busing in America,” Biden responded to Harris. “What I opposed is busing ordered by the Department of Education. That’s what I opposed.”

Across the country in the 1970s, courts were ordering schools to desegregate. In Boston, thousands of whites marched carrying U.S. and Irish flags to protest court-ordered desegregation. In Los Angeles, voters recalled the school board president.

Berkeley was different. The opposition to integration in Berkeley was quieter. An attempt to recall the school board failed.

School segregation in Berkeley had never been enforced by law in the first place. There were neighborhoods where black families could not buy houses, a tactic known as redlining, and each neighborhood had its own schools, leading to de facto segregation.

The city’s flat western side, where Harris lived as a child, was generally black, while the eastern hills were white.

Nor did the federal government have to step in to force integration: Berkeley’s comprehensive two-way busing program was undertaken by the school board voluntarily, and it was the first large city to do so when the program began in 1968.

After Harris spoke about her elementary school experience on Thursday, conspiracy theorists quickly sprung on the story, arguing that Berkeley’s schools were never segregated because some black students attended Harris’ predominantly white school before busing began. The district put out a statement on Friday supporting Harris’ account.

“Our elementary schools,” the district’s statement said, “reflected the racial composition of our neighborhoods, which like many neighborhoods across America reflected the history of segregation stemming from policies which restricted the opportunities of nonwhite residents.”

The late 1960s and early 1970s in Berkeley was a time flush with idealism, and advocates envisioned school integration ushering in a new, better society.

“We will not fail here,” the superintendent wrote in his integration report. “Where else would there be hope of success if there were failure here, in Berkeley?”

Harold Williams, 61, was at a predominantly black school when white students started being bused in, changing the demographics from 26% white to 47% white.

“It had a very positive impact on me,” said Williams, who is black and now lives in Charlotte, North Carolina. “For Kamala, or for anyone who went through it, I think it puts them in a position to have a lot of empathy.”

Other students felt they were sometimes fending for themselves in a complicated new dynamic.

“We were all just kids trying to figure it out on our own,” said Ned Garrett, 60, who is white and was bused to a black school in West Berkeley. “It stuck with me. I try to tell my kids now, ‘Don’t make assumptions, always give people a chance to show who they are.’”

Tucked away in the Berkeley Public Library are the city’s archives of the era. There in big folders are stacks of newspaper clippings. Those against busing say they worried about bus safety, travel times, neighborhood integrity and school district costs.

“To force total mixing in schools is neither constructive nor effective; individual families should have an option as to where their children go to school — and this applies to all races,” a group of Berkeley residents wrote in an open letter to the superintendent on Sept. 19, 1967.

“Berkeley was going too hard, and I don’t think they got it right a lot of the time,” said Mike Davisson, 61, who is white and was in fifth grade when he began being bused to a different elementary school. “It was scary and hard for the black kids as well as the white kids, but overall, in the end, it worked out.”

Along with integrating the students, the school district embarked on an effort to hire more black teachers.

Lynn Sherrell, 78, taught sixth grade the first year of integration.

“Among the black and white teachers there tended to be a division, and there was lunchroom segregation,” Sherrell, who is white, said. “It got ugly.”

Black faculty members were meeting separately, she said, and white teachers felt left out.

But she and her friends believed a better, less racially tense future was ahead, Sherrell said. Sometimes now she is less sure.

“It was one of the primary elements of my life and my career,” said Sherrell, who later became a tax lawyer. “We’re so much wondering now — did it do anything? Did it do any good? Was it just a big waste?”

Berkeley voted to phase out its busing program in 1994. Busing has largely been seen as a failed effort: Across the country today, schools are still segregated, and the number of intensely segregated schools is growing.

Harris has argued that school integration is one of the reasons she could become a senator. During the Supreme Court confirmation hearings for Brett M. Kavanaugh, during which Harris grilled the future justice, she also wrote about her own life.

“I wouldn’t be part of Kavanaugh’s confirmation hearings had Chief Justice Warren not been on the Supreme Court to lead the unanimous decision in Brown v. Board,” Harris posted on Twitter in September 2018. “Had someone else been there, I may not have become a U.S. Senator. I know the impact one Justice can have.”

Now, Berkeley is a wealthier and whiter town than when Harris was growing up. In 1970, the city was 23% black; today it is only 10% black. The median sale price for a two-bedroom apartment is $1.2 million, up from $682,500 just five years ago, according to the real estate listings site Trulia. Many of the historically black neighborhoods have been gentrified.

Alkebulan, who was bused to an integrated elementary school, went on to become a civil engineer, but it was housing prices that drove her out of Berkeley. She moved to Sacramento.

“I can live in Sacramento a lot better than I can in Berkeley, so we moved,” Alkebulan said. “And then we could afford to send our sons to private school.”