David Kramer, the John McCain aide who leaked the discredited Christopher Steele dossier on President Trump, testified in a libel case that he spread the unsubstantiated anti-Trump material all over Washington during the presidential transition. Mr. Kramer, a former State Department official and a Trump detractor, leaked dossier material to the Wall Street Journal, the Washington Post’s Fred Hiatt, CNN’s Carl Bernstein, National Public Radio, McClatchy news service and others, he said. But his most momentous meeting was with Ken Bensinger of BuzzFeed. In Washington during the Christmas holidays, he let Mr. Bensinger read the dossier. He then stepped away....