US official's 'quiet diplomacy' led to Warmbier's release

It took months of "quiet diplomacy," a change in U.S. presidents and an American diplomat's extraordinary, secret visit to Pyongyang to bring Otto Warmbier home.U.S. special envoy Joseph Yun was a household name to almost no one before Warmbier's return to Ohio on Tuesday, yet he joins an exceedingly short list of U.S. officials to set foot in furtive North Korea in recent years. The last such visit is believed to have been in November 2014, when former National Intelligence Director James Clapp