The rest of the Ivy League has closed ranks behind Harvard, filing a joint amicus brief, and universities across the nation are watching intently for a ruling with wide-ranging impacts.

The lawsuit says that Harvard holds the proportions of each race in its classes roughly constant and manipulates a vague “personal” admissions rating to downgrade applications from Asian-Americans. By doing this, the suit says, Harvard is violating federal civil rights law, which prohibits discrimination by universities that receive federal funds

Harvard says there is no evidence that the 40-member admissions committee has engaged in any orchestrated scheme to limit the admission of Asian-Americans. But it says that eliminating the consideration of race would cut the number of African-American, Hispanic and other underrepresented minorities by nearly half.

The lawsuit was filed in 2014 but has been generations in the making.

Suspicions that Harvard and other top colleges were imposing informal quotas on Asian-Americans to combat their quickly growing presence among the academic elite date back to at least the 1980s. In 1988, the Office for Civil Rights of the federal Education Department opened an investigation but cleared Harvard of racial discrimination.

Many remained wary. The Education Department looked into a new admissions complaint about Asian-Americans in 2012, ultimately deciding not to investigate, according to court documents. The same year, Ron Unz, a conservative activist and Harvard graduate, published a lengthy dissection of Harvard admissions, suggesting that the university was keeping down the number of Asian-American students. The essay helped rekindle public debate on the issue.

Harvard appears to have taken the criticism seriously. Around that time, an internal research group at the university conducted a study of admissions, asking, “Does the admissions process disadvantage Asians?” It found that being Asian-American decreased the chances of admission.

Much of the plaintiffs’ case echoes the findings.

Harvard says the internal study was preliminary and incomplete, and that the plaintiffs have cherry-picked data, used innuendo and taken documents out of context to arrive at their conclusions.