Affirmative action is under attack. A lawsuit filed against Harvard University might end the practice altogether. Professor Randall Kennedy of Harvard University acknowledges some of the costs of affirmative action but considers it ultimately a “positive good,” a moral necessity, and a legally defensible practice. One of the problems, he explains, is that liberals have framed affirmative action as a “win” for all, which opened the practice to attacks from conservatives who define it as an unjustified use of preferences where some win, and others lose out. Kennedy explains why affirmative action is the responsible choice in our nation burdened by a history of racial injustice – and how his own thinking has evolved in the decade from the inauguration of Barack Obama to the state we are in now. Professor Kennedy is the Michael R. Klein Professor at Harvard Law School, and the author of For Discrimination: Race, Affirmative Action, and the Law (2013).