Should citizens be treated differently based on the colour of their skin? Most people would say not, but others insist that they should—if the ends are sufficiently enlightened. Not long after America dismantled over two centuries of slavery and segregation, it embarked on a project of “affirmative action”: legally sanctioned positive discrimination for African-Americans (later expanded to other “under-represented minorities”) who wanted to go to selective universities. At the time, the affront to liberal norms of fairness and equality under the law was assuaged by the fact that the people who stood to benefit had been oppressed. Yet after 50 years with more racial progress than setbacks, an applicant to America’s top universities with the right skin colour still has a much better chance of getting in than one with identical credentials but the wrong skin colour. On June 29th the Supreme Court ended the scheme. It was right to do so. That is because affirmative action rested on contorted constitutional logic. It was also unpopular outside progressive circles. Worst of all, it didn’t work. …