idea that there are tapes of the conversation. he didn't -- still, he left a bit of a mystery but one can feel him sort of taking that tweet back. >> significant, though, that he did say in the exchange with john carl essentially, yes, i will testify, will do so under oath. >> yes. >> and historic perspective, doug, modern presidents testifying under oath. how many? put it in context for me. >> well, it's -- i do think that was an important moment. and then he added -- he said, i'm going to say exactly to mueller what i've just told you. meaning, you know, hey, there's nothing there. if he puts that under oath in a private testimony. but remember when bill clinton and the lewinsky scandal, it was a dangerous moment. bill clinton thought he was going to get out of things. we mock him for saying it all