"We cannot be guided by those who would desire less in our Constitution, or by those who would desire more. “The Constitution abhors classifications based on race, not only because those classifications can harm favored races or are based on illegitimate motives, but also because every time the government places citizens on racial registers and makes race relevant to the provision of burdens or benefits, it demeans us all.” Grutter, 539 U. S., at 353 (opinion of THOMAS, J.)."