Her experience set the stage for what happened in the crucial months that followed. In an impassioned defense of the State Department and the career Foreign Service officers who work — and sometimes give their lives — to advance the interests of the United States, Ms. Yovanovitch recounted how she became the target of a smear campaign led by Mr. Giuliani, two of his associates — Lev Parnas and Igor Fruman, who have since been indicted — and the right-wing news media.
“How could our system fail like this?” she wondered aloud. “How is it that foreign corrupt interests could manipulate our government?”
Known as Masha to her friends, Ms. Yovanovitch, a Canadian immigrant whose parents fled the Soviet Union and Nazis, was known as a vigorous fighter against corruption in Ukraine. She has become a hero to her colleagues in the diplomatic corps (a hashtag #GoMasha has sprung up on Twitter), who say what happened to her did not simply damage a single person’s reputation and career, but was also a blow to American foreign policy.
Republicans argued that Ms. Yovanovitch is, essentially, irrelevant to the inquiry, because she left before the July 25 call and because ambassadors serve at the pleasure of the president, who may recall them for any reason. And they tried to prove an unsubstantiated theory that Ukrainian officials conspired with Hillary Clinton’s campaign to interfere in the 2016 election at Mr. Trump’s expense.
Ms. Yovanovitch pushed back on the assertion.
“We all know that people are critical,” she said after Steve Castor, a lawyer for the Republicans, pointed to disparaging statements that a Ukrainian official had made Mr. Trump during the campaign. “That does not mean that someone, or a government, is undermining either a campaign or interfering in elections.”
“And I would just remind you again,” she went on, “that our own U.S. intelligence community has conclusively determined that those who interfered in the election were Russian.”
Ms. Yovanovitch was recalled from Ukraine abruptly in May, two months earlier than planned. She told lawmakers that she learned she was being pulled back from the deputy secretary of state John J. Sullivan, who called her while she was hosting an “International Woman of Courage” event honoring a Ukrainian anticorruption activist who died after having acid thrown at her.