The Supreme Court held, in the 2003 case Grutter v. Bollinger, that it is permissible for universities to give some students preference in admission on the basis of their race. That decision was a serious mistake and it is time to correct it. Grutter’s essential premise is that a racially diverse student body leads to educational benefits for all students. The Court accepted that proposition—but it should not have. There is good reason to doubt that the claimed benefits of diversity in the classroom are even genuine, much less compelling.