A former State Department official and associate of Sen. John McCain has invoked his Fifth Amendment right not to testify in connection with questions from the House Intelligence Committee about the anti-Trump dossier’s Russian sources, according to a law enforcement source. David J. Kramer, who is a central player in how the unverified Trump dossier made its way to the FBI in late 2016, testified before the committee in December in a closed-door session, indicating he had information about the dossier's sources. A subpoena was issued for mid-January, as first reported by The Washington Examiner. The law enforcement source confirmed,...