The Supreme Court on Monday heard landmark arguments over the use of race in college admissions for nearly five hours, with its six-justice conservative majority leaving the bench apparently poised to rollback a 40-year legacy of affirmative action.

Attorneys for Students for Fair Admissions, the advocacy group challenging race-conscious policies at UNC and Harvard, argued forcefully that "racial classifications" don't have a place in higher education and that the spirit of Brown v. Board of Education, the historic 1954 decision desegregating America's schools, requires race neutrality.

The University of North Carolina and Harvard, separately through their attorneys, sought to convince the court to hold the line, insisting both admissions programs adhere to the Court's precedent allowing narrowly tailored use of race as one factor in a holistic assessment of student applicants.

They repeatedly invoked lower court rulings, derived from fact-intensive district court trials, that found neither institution illegally discriminated on the basis of race. The schools also invoked the history of the 14th Amendment, drafted after the Civil War to extend equal rights to blacks and former slaves, as evidence that race-consciousness is part of our history.

The Biden administration, backing the schools in the cases, called affirmative action a "national security imperative" with significant implications for the country's future military leadership and warned of "destabilizing effects" to corporate America if the policy is abruptly curtailed.

Justices on both sides of the bench seemed to agree that the use of race as a factor in admissions should not continue indefinitely and that the court's prior rulings said as much. They disagreed strongly on how to decide when a transition to race neutrality is warranted and whether the milestone has been met.

Justice Ketanji Brown Jackson, the first Black woman justice, was a prominent voice during the first half of the arguments, repeatedly questioning the harm in considering race as one factor -- a "plus factor" -- among many in building a diverse student body. She also suggested that telling schools they cannot consider an applicants race could be a reverse violation of the Equal Protection clause.

Justice Clarence Thomas, the only conservative justice of color and second Black justice in U.S. history, cast doubt on the claimed measurable educational benefits from diversity on campus and appeared eager to overturn a series of precedents he's found egregiously wrong from the start.

There was much debate about the viability of race-neutral alternatives to assembling a diverse campus student body -- proposals that included an emphasis on socio-economic status over race, or the removal of "check boxes" while allowing applicants to raise race in an essay on their own.

In the end, many of the conservatives appeared convinced that the court's affirmative action precedent -- in practice -- was disadvantaging some students at the expense of others, purely on the basis of race -- even if quotas are not explicitly involved. That sort of favoritism has long ruffled Chief Justice John Roberts, among others, and their discomfort with the approach was on full display.

Justice Brett Kavanaugh, the justice who has voted most in the majority of any justice in the last two terms, could be an important factor in the scope of a final decision. He appeared laser focused on crafting a definition for "race-neutral" that would be workable and fair, asking several times about whether a school could give a plus factor for descendants of slaves.

The court's decision is due out next year.