Washington (CNN) Fiona Hill's extraordinary answer about her relationship with the American ambassador to the European Union was ultimately a finely distilled description of what the impeachment hearings are all about: President Donald Trump's pursuit of a "domestic political errand" that came at the expense of American foreign policy.

It was stunning in its clarity, but also that it came during the Republicans' turn for questioning.

Hill, the former senior director for Russia and Europe at the National Security Council, was several hours into her testimony when she was quizzed by the Republican staff attorney about Gordon Sondland's account of their final meeting.

Sondland had told lawmakers Hill was "pretty upset about her role in the administration, about her superiors, about the President."

"She was sort of shaking," Sondland said. "She was pretty mad."

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