The Trump administration’s new push to challenge affirmative action in college admissions has reopened a volatile debate over the role of race in the scrap for seats at the nation’s best schools — a fight that the Supreme Court had seemed to settle just one year ago.

Last June, the high court ruled — in a case involving a white student protesting affirmative action at the University of Texas — that schools could continue using race as one among many factors in admissions decisions. Colleges and civil rights advocates celebrated the decision as a recognition of their right to — and the need to — promote diversity on the nation’s campuses.

Now, activists worry that the administration’s initiative — described in an internal Justice Department memo as “investigations and possible litigation related to intentional race-based discrimination” — will sow new fears among college officials that they may be targeted for admissions policies that promote racial diversity. The memo was first made public on Tuesday evening in a report in The New York Times.

John King Jr., who was education secretary under President Barack Obama and now helms the advocacy group Education Trust, said on Wednesday he is “deeply disappointed” that the administration is choosing to spend its energies on challenging affirmative action “rather than focusing on addressing the persistent opportunity gaps facing students of color and low-income students.”

“Now is not the time to slow down on diversity initiatives or deter university leaders from doing the right thing for their communities, campuses and for our nation’s future prosperity,” King said in a statement.

Higher education leaders are mindful that for generations, until the civil rights movement, black students were systematically denied admission to leading colleges and universities. In recent decades schools have sought to widen access not only to black students but also to other groups that are underrepresented on their campuses, including those who are from low-income families or have parents who did not graduate from college.

On Wednesday, representatives from more than a half dozen colleges, stunned by news of Justice’s initiative and unclear what it meant, declined immediate comment.

Some states have outlawed race-conscious admissions policies at public universities, and some schools profess to approach admissions decisions without considering race or ethnicity. But many selective schools do consider race in their effort to create diverse classrooms and campuses. That has spurred tension and resentment — particularly at the most elite schools, where competition for seats is fierce.

The Supreme Court has said in multiple decisions that while racial quotas are unacceptable in college admissions, schools may use race as one of many factors that go into admissions decisions. But despite the court’s repeated endorsement of such diversity efforts, the country remains divided over affirmative action. Two-thirds of Americans — and 57 percent of African Americans — don’t believe that race or ethnicity should be considered in college admissions, according to a 2016 Gallup poll.

Edward Blum, who played a key role in bringing the University of Texas case to the Supreme Court, said he hopes the high court eventually falls into line with public opinion. Blum, president of the anti-affirmative action Project on Fair Representation, has since brought two additional federal cases challenging admissions policies at Harvard College and the University of North Carolina.

The Harvard case is emblematic of a new tack in the push to end affirmative action: Rather than focusing on how talented white students are rejected in favor of less-qualified minorities, the case alleges that Harvard unfairly discriminated against talented Asian American students, elevating less-qualified blacks, Hispanics and whites, in its zeal to maintain a predetermined racial balance.

“Affirmative action in America today is no longer a black-white issue. We are a multiracial, multi-ethnic nation,” Blum said. He hopes that one or both cases will eventually reach the Supreme Court and persuade the justices to put a stop to the use of race in college admissions — and he said he would welcome the Trump administration’s support.

Harvard has denied the allegations of racial discrimination, according to court documents. The university explained its view of the importance of maintaining diversity in admissions in an amicus brief filed in the most recent Supreme Court case, Fisher v. University of Texas.

“In Harvard’s experience and educational judgment, a diverse community of students adds significantly to the educational experience and future success of all of its graduates, from all backgrounds and races,” the brief says. “A campus that is home to individuals with a deep and wide variety of academic interests, experiences, viewpoints, and talents enables students to challenge their own assumptions, to learn more deeply and broadly, to develop skills of collaboration and problem solving, and to begin to appreciate the spectacular complexity of the modern world.”