The Human Rights Campaign on Saturday revoked its endorsement of Illinois Sen. Mark Kirk, two days after a racist comment he made about his opponent, Rep. Tammy Duckworth. During a debate with Duckworth, Kirk, who is running for re-election, questioned her ancestral ties to the American Revolution by invoking her Thai heritage. Kirk has since apologized for the remarks. “Attacking someone because of her race and ethnicity is inexcusable for anyone, but especially for a sitting U.S. Senator,” wrote Chad Griffin, the president of HRC. “The diversity of our movement is our greatest strength, and Senator Kirk’s remarks were an affront to our most fundamental values.” It marked the first time the group has rescinded and endorsement.