about this over the interview. we know robert mueller has threaten today subpoena him in conversations with his lawyers, subpoena him to go before a grand jury. what it sounds like from what giuliani was sailing today he doesn't know. the president could decide not to comply with the subpoena for a grand jury. that would hut him in uncharted territory. there have been three presidents who have been subpoenaed in history. this goes back to thomas jefferson. he first declined to comply, then he did ultimately give over some documents. nixon, of course, was given a subpoena. he resigned before that ever came to a head. and then bill clinton was subpoenaed and did ultimately testify. if the president decides to run that all the way up and does not comply with the subpoena, we're looking at the supreme court having to weigh in. it could be a real constitutional crisisti, somethg we've never seen. let's not talk about the politics of what that would look like, what he's trying to hide if he refuses to testify. >> let's talk briefly about politics because there was a "wall street journal" story.