“We have so much engagement and community,” said Damilola, 18, describing how the club’s previously sparse membership had grown. Its meetings now include vibrant discussions about current affairs through an African American lens.

As a freshman, she met students who seemed ignorant about Black people and made inappropriate comments. “My freshman year, I got comments that ‘You’re only at the school because of affirmative action,’” Damilola said, even though she had taken the same rigorous test as everyone else.

While she is reserving judgment on the new admissions system, she said that certain parts of it — including the geographic diversity requirement — were improvements. “It just makes things more equitable overall for everyone,” said Damilola, who is Nigerian American.

The Pacific Legal Foundation was founded in 1973, during Ronald Reagan’s tenure as California governor, by his supporters who envisioned a conservative version of the American Civil Liberties Union.

Since then, the organization, based in Sacramento, has expanded greatly. Its most recent annual budget was $17 million. Critics points to the group’s well-heeled donors and partners, including the Kochs, the Atlas Network and the Uihlein family, who operate the large business products supply company Uline, as proof that it is heavily influenced by business interests. The foundation says its support comes from 6,400 donors.

The foundation has a successful track record: 14 victories in Supreme Court cases. It is also known as a prolific filer of “friend of the court” briefs, including in support of Students for Fair Admissions, the Virginia-based group waging a legal battle against affirmative action at Harvard and North Carolina.

Mr. Driver, the Yale professor, noted that those cases pitted various ethnic groups against one another in ways that sowed division. At Thomas Jefferson, the controversy over class selection dates back decades, according to Jorge Torrico, a 1998 graduate.