Former ambassador Marie Yovanovitch began her testimony in the House impeachment hearing Friday with praise for Ukrainians who took a stand against corruption in their country in a 2014 movement called the Revolution of Dignity.

The reference doubled as a call to action that she directed at U.S. leaders — a pointed reminder of their obligation to defend the dignity of civilian career diplomats around the world.

Yovanovitch — who was abruptly yanked from her post in Kyiv after being targeted in a smear campaign that reached President Trump — warned that the State Department was “being hollowed out” and in “crisis.” She called on its leadership “to stand up for the institution and the individuals who make that institution the most effective diplomatic force in the world.”

The testimony of the former ambassador put a compelling human face on a complex international scandal that has involved a cast of unfamiliar Ukrainian characters, descriptions of shadowy back-channels and constitutional debates.

In resolute, clear tones, the veteran diplomat described how she came to learn of the plot against her — and how shaken she was to read the president’s menacing comments about her in a call to his Ukrainian counterpart.

But over and over again, Yovanovitch sought to turn the focus away from her personally and back on the larger implications of her ouster.

“Our Ukraine policy has been thrown into disarray, and shady interests the world over have learned how little it takes to remove an American ambassador who does not give them what they want,” she said. “After these events, what foreign official, corrupt or not, could be blamed for wondering whether the ambassador represents the president’s views? And what U.S. ambassador could be blamed for harboring the fear that they cannot count on our government to support them?”

The room was rapt as she spoke, with nearly every lawmaker sitting at attention or leaning in to listen as she carefully described how she was targeted by associates of Trump’s attorney, Rudolph W. Giuliani, and a series of former prosecutors in Ukraine.

Trump went after her again as she testified. “Everywhere Marie Yovanovitch went turned bad,” he tweeted about a woman who served in Somalia, Armenia and Uzbekistan.

Democratic lawmakers immediately accused him of witness intimidation and House Republicans in the hearing refrained from similar attacks, some of them offering extensive praise for her service.

They sought to parry her testimony largely by arguing that it was irrelevant to the impeachment probe into whether the president abused his power.

“We’re learning a whole bunch about her feelings, but . . . she doesn’t have any relevant facts,” Rep. Mark Meadows (R-N.C.) told reporters during a break in the testimony.

Some Republicans accused Democrats of trying to use Yovanovitch to inject drama into the hearings for the watching audience.

“They wanted her to cry for the cameras,” Rep. Lee Zeldin (R-N.Y.) told reporters, referring to how Yovanovitch became emotional during her closed-door deposition last month when describing the circumstances of her firing.

At one moment Friday, Yovanovitch appeared to hold back tears when she was asked by Rep. Terri A. Sewell (D-Ala.) how it felt personally to have her reputation sullied. “It was a difficult time,” she said, shaking her head. “I’m a private person. I don’t want to put all that out there.”

But for much of the day, she was composed, and her voice was precise and clear as she sat straight-backed on the edge of her chair for more than five hours fielding questions.

“I obviously don’t dispute that the president has the right to withdraw an ambassador, at any time for any reason,” said the 33-year veteran of the Foreign Service who has served under Republican and Democratic presidents. “But what I do wonder is, why was it necessary to smear my reputation?”

When asked by Intelligence Committee Chairman Rep. Adam B. Schiff (D-Calif.) why she didn’t defend herself more openly to the attacks against her, she added: “I think it was for others to stand up for me.”

However, Secretary of State Mike Pompeo never made a statement in her defense because he was worried Trump would undermine it in a tweet, Yovanovitch testified that she was told.

Yovanovitch is in many ways the opposite of Trump: soft-spoken, physically slight and, on Friday, prone to deflecting attention away from herself, even as she was the focus of a presidential impeachment hearing.

But throughout the hearing, Yovanovitch was steely in her defense of the diplomats and institutions that promote U.S. policy abroad without weapons. She invoked the memory of everyone from the hostages in Iran to the felled in Benghazi in her appeal to respect and defend the Foreign Service against those who would undermine it — including the Trump administration.

She also voiced her continued concern for Ukraine, pledging to Rep. Eric Swalwell (D-Calif.) that she would endeavor to continue fighting corruption there.

At one point, Rep. Will Hurd (R-Tex.), a former CIA officer who is seen as a potential wild card in the GOP on impeachment, applauded Yovanovitch.

“You’re tough as nails and you’re smart as hell,” he said. “You’re an honor to this country and I thank you.”

At the end of the day, as Yovanovitch departed the hearing room, members of the public in the audience leaped to their feet, giving her an extended standing ovation.