The Trump administration’s planned investigation into affirmative action in a college admissions case 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.

In June 2016, 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 an internal Justice Department job posting seeking lawyers to work on “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 Tuesday evening in a report in the New York Times.

On Wednesday evening, the department said the posting was not an indication of a broad policy change but rather an effort to prioritize a complaint filed by Asian Americans in May 2015, alleging discrimination in university admissions.

John B. King Jr., who was education secretary under President Barack Obama and now helms the advocacy group Education Trust, said 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.

Susan Sturm, director of the Center for Institutional and Social Change at Columbia Law School, said she worries that some universities may stop using race in admissions decisions, a problem “at a time when leadership around addressing a polarized racial environment in our country is just so critically important, and where the capacity to bridge these growing economic, racial, educational divides is critical to the prosperity of our democracy.”

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.

On Thursday, June 23, 2016 the U.S. Supreme Court voted, 4-3, to uphold an affirmative action ruling in the Fisher v. UT Austin case. It's a surprising win for affirmative action advocates. Here's what you need to know. (Monica Akhtar, Gillian Brockell/The Washington Post)

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. Yet a 2013 Pew Research survey found 63 percent favor programs aimed at boosting the number of black and minority students on college campuses.

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 University and the University of North Carolina at Chapel Hill.

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.

“To become leaders in our diverse society, students must have the ability to work with people from different backgrounds, life experiences and perspectives,” the university said Wednesday in a statement. “Harvard remains committed to enrolling diverse classes of students. Harvard’s admissions process considers each applicant as a whole person, and we review many factors, consistent with the legal standards established by the U.S. Supreme Court.”

The federal government has at times investigated complaints of racial discrimination in college admissions outside of the courts — including at Harvard. The Education Department examined whether Harvard discriminated against Asian Americans nearly three decades ago, concluding in 1990 that it did not. Though Asian Americans were admitted at a lower rate than white students, that was the result of prioritizing the admission of children of alumni, the department found, not the result of racial quotas.

In 2015, the department concluded in another case that Princeton University had used race as one of many factors in its effort to assemble a diverse student body — and therefore did not discriminate against Asian American students.

While conservatives have long pushed to do away with race-conscious admissions policies, the debate over race-conscious admissions policies does not always cleave neatly along political lines.

Richard Kahlenberg, a senior fellow at the left-leaning Century Foundation and self-described progressive, has long argued that colleges could achieve more diversity by focusing on socioeconomic class rather than race. Affirmative action policies to date have benefited mostly middle- and upper-class students, Kahlenberg said, while students from low-income backgrounds remain drastically underrepresented.

“It will be tempting for progressives like me to say that a challenge to affirmative action at elite universities is another example of Donald Trump beating up on minorities, like the Muslim ban or the transgender bar in the military or voter suppression,” Kahlenberg said. But in his view, Trump’s critics should reconsider their allegiance to race-based affirmative action.

“I would strongly argue that advocating for policies on behalf of disadvantaged students, who are disproportionately students of color, is far more progressive than advocating for the current set of policies which tend to benefit advantaged students of all colors.”