on a friday night, good evening once again from our nbc news headquarters here in new york. day 554 of the trump administration, and the president escalates the war on his former lawyer and confidante, michael cohen, while denying that he had any advanced knowledge about that june 2016 meeting in trump tower. a source has told nbc news cohen is willing to tell robert mueller that donald trump jr. informed his father about the meeting before it took place. trump's son had that meeting with several russians after he was told they were coming prepared with damaging information about hillary clinton. well, today the president responded with this -- "so, the fake news doesn't waste my time with dumb questions, no, i did not know of the meeting with my son, don junior. sounds to me like someone is trying to make up stories in order to get himself out of an unrelated jam. taxi cabs, maybe?" we'll explain that one. "he even retained bill and crooked hillary's lawyer.