WASHINGTON (AP) — The Supreme Court ruled Thursday that colleges and universities must stop considering race in admissions, forcing institutions of higher education to look for new ways to achieve diverse student bodies.

In a 6-3 decision, the court struck down admissions plans at Harvard and the University of North Carolina, the nation’s oldest private and public colleges, respectively.

Many universities have argued that race-based admissions ensures that student bodies remain diverse, while critics such as the plaintiffs in the cases argue the policy discriminates against many qualified students based on race.