With less than a week to go until South Dakota voters decide whether to send their former governor, Mike Rounds, to the U.S. Senate, the FBI for the first time publicly acknowledged the existence of an ongoing investigation into the state’s management of a federal visa program during Rounds’s tenure as governor, between 2003 and 2010. The statement breathed new life into a controversy that many thought had long since died out and that is now being used against Rounds on the campaign trail. The FBI’s confirmation came nearly three years after a Texas lawyer reportedly notified the FBI of...