it is just the latest in the rapid succession of closed door and public testimony. there's more closed door testimony tomorrow then of course next week. there are those eight witnesses testifying in public. >> yeah, it's going to be a very, very significant, indeed. perhaps totally critical. thanks very much. president trump meanwhile is citing freedom of speech. as democrats him of witness intimidation with his twitter attack on the former u.s. ambassador to ukraine while she was testifying. let's go to our chief white house correspondent, jim acosta. some of the president's allies may think he made a significant mistake. >> that's right. a clearly frustrated president trump defended his tweet aimed at yovanovitch argued he had the right to free speech as much anybody else. he got testy on whether his tweet amounted to witness intimidation or tampering. two trump campaign sources i talked to today sharply