Harvard University can racially discriminate in admissions against Asian-Americans to achieve a more diverse student body. That’s the startling essence of a federal judge’s ruling Tuesday that turns the 1964 Civil Rights Act on its head and seems destined for the Supreme Court.

“Ensuring diversity at Harvard relies, in part, on race conscious admissions,” wrote federal Judge Allison Burroughs. “Race conscious admissions will always penalize to some extent the groups that are not being advantaged by the process, but this is...