A State Department official testified Tuesday that Rudy Giuliani, President Trump’s personal lawyer, conducted a smear campaign against the U.S. ambassador to Ukraine and tried to “gin up” politically motivated investigations into Joe Biden and his son.

George Kent was one of two kick-off witnesses in the House impeachment investigation into whether Trump abused the power of his office in a bid to get political dirt on political rivals. The committee wants to know whether Trump illegally withheld $391 million in military aid in exchange for investigations into unfounded allegations against the former vice president, one of the 2020 candidates for the Democratic nomination.

“It was unexpected, and most unfortunate however, to watch some Americans — including those who allied themselves with corrupt Ukrainians in pursuit of private agendas — launch attacks on dedicated public servants advancing U.S. interests in Ukraine,” Kent said in his opening statement. “In my opinion, those attacks undermined U.S. and Ukrainian national interests and damaged our critical bilateral relationship.”

He explained that U.S. interests are in alignment with Ukraine “in the way we have defined our national interests broadly in Europe for the past 75 years.” He said the behavior he observed undermined that.

Kent said he watched some people allied with corrupt individuals in Ukraine pursue private agendas and smear U.S. Ambassador to Ukraine Marie Yovanovitch.

"Over the course of 2018 and 2019, I became increasingly aware of an effort by Rudy Giuliani and others ... to run a campaign to smear Ambassador Yovanovitch and others in the U.S. embassy in Kiev," Kent testified.

Trump characterized the impeachment hearing as a “joke” and a “sham.”

“It shouldn’t have been allowed,” Trump said, adding that he hadn’t watched any of the proceedings.

Republicans attacked the proceedings, saying none of the testimony proves Trump did anything wrong.

Rep. Devin Nunes, R-Calif., congratulated both Kent and acting U.S. Ambassador to Ukraine William Taylor for passing at what he described as the “Democrats’ star chamber auditions.” He called the hearings a “televised theatrical performance.”