Jennifer Williams, an aide to Vice President Mike Pence since April, is testifying on Capitol Hill Thursday about her role in the Ukraine controversy fueling the House's impeachment inquiry.
Williams, a longtime foreign service officer based in London, joined Pence's team to advise on Europe and Russia matters just as President Donald Trump's posture toward Ukraine threw the foreign policy establishment into disarray.
It's unclear if Williams is testifying under subpoena. Though the White House has ordered officials to refuse cooperation with the impeachment probe, a dozen National Security Council and State Department officials have sought subpoenas to circumvent the order. Williams is the first official from Pence's office to testify.
Trump abruptly recalled the U.S. Ambassador to Ukraine, Marie Yovanovitch, amid a smear campaign by the president's allies to portray her as disloyal to Trump. And Trump's personal lawyer, Rudy Giuliani, had pressured Ukrainian officials to investigate Joe Biden and debunked theories that Ukraine - not Russia - was behind the 2016 hacking of the Democratic National Committee.
Pence was on the July 25 call between Trump and Ukraine's newly elected president Volodymyr Zelensky when Trump directly urged him to investigate the Bidens. Pence was also dispatched to meet Zelensky in Warsaw after Trump canceled a planned meeting there.
House impeachment investigators have requested documents from Pence's office, but he has declined to provide them.