Firing Line With Margaret Hoover

Guest: Sen. Mark Warner (D-VA). Sen. Intel Vice Chair Mark Warner (D-VA) discusses Russian election interference and how other adversaries have learned from their playbook heading into 2020. Warner talks about combating threats to voting systems and disinformation campaigns. He also discusses his possible role as a juror in an impeachment trial, and says Russian spies spread the false claim that Ukraine meddled in the 2016 election.