Sen. Joe Donnelly (Ind.), a conservative Democrat in one of the tightest reelection battles in the country, made a cringeworthy and puzzling statement about some minorities on his staff during a debate Tuesday night. To begin, here’s a quick vocab refresher. The definition of the word “but,” according to Google, is “to introduce something contrasting with what has already been mentioned." So it was strange when Donnelly, in what seemed like a genuine effort to compliment his aides, said this when asked how he would bring diversity into his staffing: “Our state director is Indian American, but he does an...