Which Supreme Court case ruled that "affirmative action" is constitutional?

The case that is most prominently associated with the ruling on the constitutionality of affirmative action is Grutter v. Bollinger. This 2003 Supreme Court decision upheld the use of affirmative action in college admissions, stating that institutions of higher education could consider race as one factor among many in order to promote diversity within their student bodies.

The earlier case, Regents of the University of California v. Bakke, decided in 1978, also addressed affirmative action but struck down a quota system in medical school admissions while allowing for race to be considered as one factor in admissions. Both cases contribute to the evolution of affirmative action policies in the United States, but it is Grutter that more explicitly reaffirmed the constitutionality of the practice in the context of higher education.

Thus, Grutter v. Bollinger serves as the landmark case that solidified the legal standing of affirmative action, clearly establishing precedents that influence how race can be factored into admissions processes under the Equal Protection Clause of the Fourteenth Amendment.