The U.S. Supreme Court is expected to rule on the consideration of race in college admissions this month.

Justices are considering two cases brought by Ed Blum, a white man and conservative legal activist, and his group Students for Fair Admissions. They challenge the constitutionality of affirmative action policies at Harvard University and UNC-Chapel Hill, alleging they harm white and Asian American students.

The decision could severely restrict efforts by universities to make their campuses more diverse and racially representative.

There is a lot of confusion about how the policy actually works on college campuses. As we await the decision, here are six things to know.

It was initially a form of reparations — not a way to diversify predominantly white institutions

Leaders of universities in the North were prompted by the Civil Rights movement to make amends for centuries of racial oppression that led to the exclusion of communities of color from higher education, according to sociologists Lisa Stulberg and Tony Chen.

“There were no discriminatory laws on the books in states like Washington or Michigan. And yet there were so few Black students on campus,” Chen told WBEZ. “So the men at these institutions decided to begin exploring new ways of thinking about academic merit in order to bring African American students on campus.”

The first affirmative action policies at universities took root in the 1960s. They often involved sending admissions recruiters to urban high schools that served Black and brown students. Later in the decade as institutions faced mounting pressure from civil rights activists, some started set aside programs in which a number of spots were reserved for marginalized students.

Racial quotas are no longer allowed

The use of quotas, or set asides, was found to be unconstitutional in 1978. A white applicant rejected twice from the University of California Davis medical school challenged the school’s affirmative action policy.

The university reserved 16 of 100 seats for disadvantaged minorities, in part to remedy the impacts of past discriminatory practices. Attorneys for Allan Bakke, the applicant, argued this violated the Equal Protection Clause of the 14th Amendment.

The case reached the Supreme Court in 1978. The justices ruled that promoting educational opportunities for minority students equated to discrimination against their white peers.

From that point on, universities were limited to using race as just one of many factors in admissions decisions – and could no longer provide an advantage to marginalized students as a way to compensate for systemic racism. Race-conscious admissions, as these policies came to be known, could only be used to boost campus diversity for its educational benefits.

“What’s at stake in the Harvard and UNC cases [before the Supreme Court] is a much more modest program called holistic review, where students are all part of a common pool,” said Chen. “Their applications are examined individually … and race is considered as one of many different factors that can add value to their application.”

Nowadays race may be used as a tiebreaker

Selective universities usually have multiple extremely qualified applicants vying for each available spot. After application readers assess transcripts and extracurriculars, they look to other traits to help decide between students, like race, alumni relationships, or socioeconomic status.

“They get a huge pile of applications,” said James Murphy, higher education policy director for Education Reform Now. “And for sure, a bunch of them all can be just swept out. ‘You’re not in contention.’ But there’s still, for every spot, probably five, six, seven students who could fill that spot. So once you get past the academic qualifications, then you have to start looking at other things.”

The traits considered, Murphy said, connect back to an institution’s mission and priorities, like socioeconomic diversity, or building support amongst graduates. (Remember, an institution cannot publicly justify considering race as a way to remedy the effects of racial inequality).

Bans on race in admissions have brought detrimental impacts for students of color

After California voters banned the consideration of race in admissions in 1998, fewer underrepresented minorities in the state earned undergraduate and graduate degrees, according to an analysis by Zachary Bleemer, assistant professor of economics at Yale University. By the mid-2010s, his study found, the ban had led to a 3% decline in the number of Californians of color earning more than $100,000 early on in their careers.

Opponents of affirmative action often argue that universities can make their campuses more representative of the country’s racial makeup without considering race. But research by Georgetown University’s Center on Education and the Workforce found that substituting potential proxies for race, like socioeconomic and first generation status, does not significantly increase the share of underrepresented minorities at selective universities.

The researchers found the only way to compensate for a ban on affirmative action would require upending college admissions at these institutions, “including by greatly expanding the pool of candidates considered for admission and eliminating admission preferences for privileged groups.” That includes legacy admissions, or preference for family members of alumni. Locally, both the University of Chicago and Northwestern University have continued this practice, despite criticism.

The ruling could reach beyond college admissions

Scholarships and support programs for students of color could be affected, too, since they take race into consideration. And some experts say the decision could have impacts beyond higher education – on hiring policies aimed at diversifying the workforce, for instance.

Potentially affected colleges represent a small slice of higher ed

“[Affirmative action] mostly impacts highly selective colleges,” said Murphy of Education Reform Now. “And they are tiny, right? The entire Ivy League enrolls fewer Pell students [from low-income households] every year than Rutgers University.”

But diversifying these institutions and making them more equitable matters, he said, because they graduate many of society’s most powerful and influential leaders.

Lisa Philip covers higher education for WBEZ, in partnership with Open Campus. Follow her on Twitter @WBEZeducation and @LAPhilip.

Higher education reporter for WBEZ Chicago in partnership with Open Campus.