Transcript for The biggest moments in former US Ambassador Marie Yovanovitch’s hearing
Reporter: By 8:30 this morning, it was clear this would be standing room only. The long line of spectators in the marble corridor seemed to stretch back forever. The house impeachment showdown has instantly become "The" marquee event in Washington. Start time, 9:00 A.M. Sharp. The battle lines drawn. Mr. Chairman, I want you to release the full transcript of the depositions. This is historic, and I think everyone in that hearing room feels the gravity of history on them. Reporter: Today's witness, one of the most senior diplomats, Marie yovanovitch. Do you swear or affirm -- Reporter: President trump abruptly recalled her last spring. She testified today she was kneecapped through a smear campaign led by a corrupt Ukrainian prosecutor and president trump as lawyer, Rudy Giuliani. I do not understand Mr. Giuliani's motives for attacking me, nor can I offer an opinion on whether he believed the allegations he's read about me. Clearly no one at the state department did. Reporter: She said the order to leave Ukraine came in a 1:00 A.M. Phone call in late April. She was told to get on the next plane back to Washington. How did that make you feel? Terrible, honestly. I mean, after 33 years of service to our country, it was terrible. It's not the way I wanted my career to end. In your 33 years as a foreign service officer, have you ever heard of a president of the United States recalling another ambassador without cause based on allegations that the state department itself new knew to be false? No. Reporter: In his July 25th phone call with president Zelinsky, the president bad mouthed yovanovitch, calling her "Bad news." I was shocked and absolutely devastated, frankly. What do you mean by devastated? A person who saw me actually reading the transcript said the color drained from my face. I think I even had a physical reaction. I think, you know, even now words kind of fail me. Reporter: According to the call summary, trump then confided she's going to go through some things. She's going to go through some things. Didn't sound good. Sounded like a threat. Did you feel threatened? I did. How so? I didn't know exactly. It's not, you know, a very precise phrase, but I think it didn't feel like I was, I really don't know how to answer the question any further except to say that it kind of felt like a vague threat. Reporter: Within minutes of yovanovitch's testimony about being smeared -- As we sit here testifying, the president is attacking you on Twitter. Reporter: The president lashed out in real time from the white house. I'll read part of one of his tweets. Everywhere Marie yovanovitch went turned bad. She started off in Somalia, how did that go? What would you like to respond to the president's attack that everywhere you went turned bad? I, I mean I, I don't think I have such powers. I'm not in Mogadishu, Somalia and other places. I actually think that where I've served over the years I and others have demonstrably made things better. Anytime women challenge the president of the United States, it seems to strike a nerve in him and get a reaction that's a bit more visceral. And now the president in real time is attacking you. What effect do you think that has on other witnesses' willingness to come forward and expose wrongdoing? It's very intimidating. Designed to intimidate, is it not? I mean, I can't speak to what the president is trying to do, but I think the effect is to be intimidating. Well, I want to let you know, ambassador, that some of us here take witness intimidation very, very seriously. Ive been watching today for the first time. Reporter: A few hours later, the president brushed off any suggestion of witness tampering. Sir, do you believe the words could be intimidating in. I don't think so at all? The question is, does this get lumped into a broader issue of impeachment on witness intimidation? I think it's unlikely, but you never know. And you certainly heard congressman Schiff explaining that's a possibility. Reporter: In kiev, watching the testimony unfold as well, Daria, an anticorruption activist who worked closely with yovanovitch when she was stationed there. She was our true supporter and friend. She was very professional diplomat. Very soft-spoken. And she was very much committed to the success of Ukraine as a democratic control of law. Reporter: She says it's clear why she was pushed out. She was hated by people who are kooks. She was hated by some people in the Ukrainian government whom she pressed to deliver reforms in appointment corruption. And right in the middle of Marie yovanovitch's testimony. We're going to take a brief recess. That's when a few blocks away we get the verdict on the Roger stone case. The kind of thing that only happens in Washington. Reporter: President trump's long-time friend and political operative, Roger stone was convicted of lying to congress and witness tampering. The same committee holding a hearing today is the one where Roger stone has been convicted for lying to or obstructing. Reporter: Stone could face as much as 50 years in prison. There's no question that the president is empowered to pardon Roger stone on any or all of the charges. Reporter: Then late in the day behind closed doors, the intelligence committee heard from David Holmes, an embassy staff member who says he overheard president trump on the phone with ambassador Gordon sondland in kiev. According to Holmes' opening statement obtained by CNN, sondland agreed the president did not give an S about Ukraine and said that the president only cares about, quote, big stuff, big stuff that benefits the president, like the Biden investigation. What's significance there? This new information is a bombshell. The fuse was lit on Wednesday when ambassador Taylor mentioned that this witness overheard this conversation first hand. And today you saw the fuse and the bomb go off. Now that we have another witness coming forward admitting that they overheard the president's actual voice, it takes away the Republicans' argument that this is all just hearsay. In my line of work, perhaps in your line of work as well, all we have is our reputation. And so this has been a very painful period. How has it affected your family? I really don't want to get into that. Thank you for asking me. Reporter: Today's hearing was at times emotional, especially over the shabby treatment ambassador yovanovitch received. It wasn't your preference to be the victim of a smear complain, was it? No. It wasn't your preference to be defamed by the president of the United States, including today, was it? No. It's not the end of a hallmark movie. It's the end of a really bad reality TV show, brought to you by someone who knows a lot about that. Reporter: The main Republican push back, that her testimony is not relevant to impeachment. Do you have any information regarding the president of the United States accepting any bribes? No. Do you have any information regarding any criminal activity that the president of the united States has been involved with at all? No. Reporter: And that the president is entitled to change ambassadors if he likes. I obviously don't dispute that the president has the right to, to withdraw an ambassador at any time. For any reason. But what I do wonder is why it was necessary to smear my reputation falsely. I wasn't asking you about that, but thank you very much, ma'am. We've had compelling testimony this week of people with real credibility and authority that really, you know, pulls at your patriotic heartstrings of these people going to hardship places and fighting for our democracy. And it's those people against Donald Trump. These are strong, important people who are doing important jobs. And even if you don't agree with what they're doing -- She didn't deserve this. She doesn't deserve this. Reporter: Today's hearing made that point loud and clear. The bigger question remains. Does the president deserve to be impeached? I'm David Wright for "Nightline" in Washington.
This transcript has been automatically generated and may not be 100% accurate.