I dealt with a lot of convicted felons in the course of my 25 years in the FBI, but I have to say the President’s former fixer cut a pretty convincing figure as trusted consigliere turned cooperating witness in the course of often emotional testimony. For the most part, he kept his cool in the face of withering, highly personal criticisms from those surprisingly uninformed Republicans on a range of issues. He was particularly effective at laying out a number of allegations, some backed by documentation, about possible criminal activities of a sitting US president.