take to lift a whole on u.s. military aid in ukraine. it would hang on whether or not president zelensky was able to trust president trump. reporter: in a meeting, saying bolton was involved in many relevant conversations and meetings that have not been discussed in the testimony thus far. what could we have witnessed? john bolton would have had more than anything we ve heard to date. anything that the president said in john bolton s presence about the pressure campaign on the ukrainians would be enormously significant testimony. reporter: including one meeting that an aide testified bolton had with trump in august, where the aide said bolton tried and failed to get trump to lift the hold on u.s. military aid to ukraine. among the crucial looming questions are, when will john bolton reveal what will he knows about the yuge dealings and in
but former national security adviser john bolton could know more about all of the allegations that president trump could have used his power to investigate joe and hunter biden. john bolton has been one of the most mysterious figures. he was one of the biggest starring players in the whole episode with ukraine. and yet, he was an off-stage character almost the entire time in the impeachment probe. reporter: but on friday, after more than two months of silence, a tease from john bolton. in a series of tweets and later with an encounter with reporters, he accused the white house of blocking his twitter account. they attached software to it. and twitter unattached the software to it. reporter: bolton didn t explain what that meant. president trump and the white house denied blocking and freezing bolton s twitter account. no, of course not. of course not. i actually had a good relationship with john. reporter: in a tweet, bolton asked whether twitter blocked
what forum? bolton s lawyer said he wouldn t testify at impeachment hearings, unless a judge forced him to. and he wasn t subpoenaed by house democrats. but he might have to testify at a senate impeachment trial. or bolton s first revelations could come in a new book he s writing which is due out next year. sometime before the i election. brian todd, cnn, washington. joe biden has some strong words for republican senator lindsey graham. he spoke with cnn s don lemon in the key state of south carolina friday. here he is. let me ask you, because lindsey graham now, who you ve worked with, who was a friend, who i know there s a video of you saying you re the nicest person he ever met. you re the greatest man. and now he s asking the state department for documents of you and your son. what do you say to lindsey graham and folks like him? they re asking lindsey graham, they have him under
his account, quote, out of fear of what i might say. in accounts that his top aide fiona hill said about bolton s concerns about pressure in ukraine. he then said that rudy giuliani was a hand grenade that was going to blow everyone up. reporter: hill said bolton physically stiffened at a july meeting when u.s. ambassador gordon sondland first linked to ukraine investigating the bidens. hill said bolton immediately walked out of the meeting and gave her an ominous directive afterwards. specific instruction was that i had to go to the lawyers, to john eisenberg, our senior council for the national security council, to basically say you tell eisenberg, ambassador bolton told me, i m not part of whatever drug deal that mulvaney and sondland are cooking up. reporter: and american diplomat david holmes testified that bolton met with ukraine s president in august. and warned him what it would
that took place the day after giuliani provided a package to the state department containing unproven allegations against u.s. democratic candidate joe biden and his son hunter. a lawyer representing an indicted associate of president trump s attorney rudy giuliani announced that devin nunes met with ex-ukrainian officials last year. nunes denied multiple requests for comment from cnn. a series of tweets on friday from former national security adviser john bolton attracted a lot of attention mostly because of what they said and because bolton has been silent since leave the post. here s cnn s brian todd with more about it. reporter: he s been one of the ghosts of the impeachment hearings, on a list of key figures like mike pompeo, rudy giuliani and mick mulvaney who didn t testify.