In a little-noticed interview in April, former Australian diplomat Alexander Downer spoke publicly for the first time about his barroom conversation with President Donald Trump’s campaign adviser that would serve as a catalyst for the FBI’s collusion investigation. Downer, the former high commissioner to the U.K., said he asked another Australian diplomat to contact the Trump aide, George Papadopoulos, for the meeting, which occurred around May 10, 2016, at London’s Kensington Wine Room. Over drinks, Papadopoulos mentioned Russians had information on Hillary Clinton that could prove damaging, Downer told The Australian in an April 28 interview. There was no indication...