In the 1970s, strict racial quotas were declared unconstitutional primarily on the grounds of the Equal Protection Clause of the Fourteenth Amendment to the United States Constitution. This clause prohibits states from denying any person "the equal protection of the laws," which has been interpreted by the Supreme Court to mean that the government cannot discriminate on the basis of race.
One of the landmark cases that addressed this issue was Regents of the University of California v. Bakke (1978). In this case, the Supreme Court ruled that while affirmative action programs that aim to increase diversity and address past discrimination are permissible, strict racial quotas that set aside a certain number of spots exclusively for minority applicants were unconstitutional. The Court determined that such quotas violated the Equal Protection Clause by discriminating against individuals based on race, including those who were not part of the targeted minority groups.
The decision acknowledged the importance of striving for diversity and combating historical racial injustices but emphasized that admissions processes must be individualized and not rely on fixed numerical goals based solely on race. This reasoning underscored a constitutional commitment to equality and non-discrimination.