Supporters march during a rally in support of affirmative action policies outside the Supreme Court in Washington on Oct. 31. Eric Lee/The Washington Post

The Supreme Court decision Thursday striking down racial-preference admissions policies at Harvard University and the University of North Carolina came 45 years after a landmark ruling allowing such affirmative action policies as a necessary option for building diverse student bodies.

In between came several other rulings, each reflecting a sharp split over what the Constitution and federal law allow.

“A State’s use of race in higher education admissions decisions is categorically prohibited by the Equal Protection Clause,” Justice Clarence Thomas wrote in 2013.

“The stain of generations of racial oppression is still visible in our society, and the determination to hasten its removal remains vital,” Justice Ruth Bader Ginsburg wrote in 2003.

Here’s a look at some of the court’s most important past affirmative action decisions, which laid the groundwork for Thursday’s rulings.

REGENTS OF THE UNIVERSITY OF CALIFORNIA V. BAKKE 1978

Issue: Whether a program at the UC Davis medical school that reserved 16 of every 100 spots for minority students was discriminatory. Allan Bakke, a White man who was denied admission even though he had higher test scores than admitted minority students, challenged the policy.

Decision: The court struck down the medical school’s quota system but upheld the use of affirmative action to build a diverse student body.

The case splintered the court 4-4-1, with six of the nine justices writing opinions.

Chief Justice Warren E. Burger and Justices Potter Stewart, William H. Rehnquist, and John Paul Stevens said Bakke should be admitted.

Justices William J. Brennan Jr., Byron White, Thurgood Marshall, and Harry Blackmun disagreed, saying “government may take race into account when it acts not to demean or insult any racial group, but to remedy disadvantages cast on minorities by past racial prejudice.”

The controlling opinion was written by Justice Lewis F. Powell. The second group of liberal justices joined the part of his opinion in which he said race could be used as a factor in admission decisions to build a racially and culturally diverse student body. But the first group of justices joined the part of his opinion in which he said the medical school’s quota system was discriminatory and should be struck down. They said Bakke should be admitted, and he was.

GRATZ V. BOLLINGER AND GRUTTER V. BOLLINGER 2003

Issue: Whether affirmative action programs regarding undergraduate and law school admissions at the University of Michigan are discriminatory.

In Gratz, the challenge was to a program that granted minority undergraduate applicants a 20-point bonus. It was struck down in an opinion by Chief Justice Rehnquist, who wrote that a program “which automatically distributes 20 points, or one-fifth of the points needed to guarantee admission, to every single ‘underrepresented minority’ applicant solely because of race, is not narrowly tailored to achieve the interest in educational diversity that [university officials] claim justifies their program.”

He was joined by Justices Sandra Day O’Connor, Antonin Scalia, Anthony M. Kennedy, and Thomas. Justice Stephen G. Breyer joined in the outcome of the case, but not Rehnquist’s reasoning.

Justices Stevens, David H. Souter, and Ginsburg dissented.

In Grutter, the challenge was to a law school program that considered race as one factor in making admission decisions. O’Connor, writing for the majority, said the individualized consideration passed muster. “We endorse Justice Powell’s view that student body diversity is a compelling state interest that can justify the use of race in university admissions.”

But she added: “We expect that 25 years from now, the use of racial preferences will no longer be necessary to further the interest approved today.” She was joined by Stevens, Souter, Ginsburg, and Breyer.

Rehnquist, Scalia, Kennedy and Thomas dissented. Thomas wrote that, like abolitionist Frederick Douglass, he believed “blacks can achieve in every avenue of American life without the meddling of university administrators.” He said the Constitution does not “tolerate institutional devotion to the status quo in admissions policies when such devotion ripens into racial discrimination.”

FISHER V. UNIVERSITY OF TEXAS (FISHER I) 2013

Issue: Whether, after automatically admitting Texans who finished in the top 10 percent of their high school classes, UT officials could use race as a factor in filling out the rest of its class. Abigail Fisher, a White woman who was denied admission, challenged that discretionary part of the process.

Decision: The court punted, voting 7-1 to send UT’s admission policy back for further judicial view, and told the lower court to apply the kind of rigorous evaluation that must accompany any government action that considers race.

“Strict scrutiny imposes on the university the ultimate burden of demonstrating, before turning to racial classifications, that available, workable race-neutral alternatives do not suffice,” wrote Kennedy.

He was joined by Chief Justice John G. Roberts Jr. and Justices Scalia, Thomas, Breyer, Samuel Alito, and Sonia Sotomayor.

Ginsburg was the lone dissenter, saying the lower court already had done the work and upheld the program. Justice Elena Kagan recused herself because she had worked on the case as U.S. solicitor general.

FISHER V. UNIVERSITY OF TEXAS (FISHER II) 2016

Issue: After the U.S. Court of Appeals for the 5th Circuit on remand again upheld UT’s use of race, Fisher and the organization headed by Edward Blum – who is also behind the Harvard and UNC challenges – convinced the Supreme Court to again take up the case.

Decision: In a surprising 4-3 win for affirmative action advocates, Kennedy joined with the court’s liberals to reiterate that diversity justifies some intrusion on the Constitution’s guarantee of equal protection.

“Considerable deference is owed to a university in defining those intangible characteristics, like student body diversity, that are central to its identity and educational mission,” wrote Kennedy, who had never before voted in favor of a race-conscious plan.

He was joined by Ginsburg, Breyer, and Sotomayor.

Justices Roberts, Thomas, and Alito dissented. “Something strange has happened since our prior decision in this case,” is how Alito began his lengthy dissent, characterizing the UT policy as “affirmative action gone wild.”

Kagan again was recused. Scalia died between oral arguments in the case and the decision.