Witness: Trump knew Jan. 6 crowd was armed when he directed them to march to the Capitol

Tonight on the Last Word: Donald Trump attacks the credibility of Cassidy Hutchinson after her damning testimony before the January 6th Committee. Also, Mary Trump reacts to the claim of her uncle’s violent outbursts. Plus, the January 6th Committee shares messages received by witnesses and warns against witness intimidation. And votes are being counted in eight states. Rep. Adam Schiff, Barry Berke, Neal Katyal, Olivia Troye, David Cay Johnston, Tim O’Brien, Andrew Weissman and Steve Kornacki also join Lawrence O’Donnell.