The first day of impeachment hearings against President Donald Trump included new evidence from the acting U.S. Ambassador to Ukraine, who told lawmakers that one of his aides had listened to a top U.S. diplomat speak with the President, reporting that Mr. Trump had inquired repeatedly about political investigations he was seeking. William Taylor told the House Intelligence Committee that since his recent deposition in October, one of his staffers had reported the unsecured cell phone call between U.S. Ambassador to the European Union Gordon Sondland and the President, saying the message was clear. 'President Trump cares more about the investigation of Biden, that Giuliani was pressing for,' Taylor told the first day of impeachment hearings. At the White House, the President denied the assertion by Taylor, telling reporters he did not remember any such call with Sondland, which Taylor said occurred a day after a July 25 phone call with the leader of Ukraine, where the President asked for Ukraine to start certain political investigations. In the hearing, Taylor and State Department official George Kent repeatedly found themselves trying to walk an almost impossible tightrope of being a truth-telling non-partisan diplomat, thrust into the midst of a politically explosive impeachment hearing, in which their every answer could be used by one party or the other to buttress or undermine their impeachment arugments. 'I'm not here to do anything having to do with, to decide about impeachment.' Taylor said at one point to Rep. John Ratcliffe (R-TX). 'That is not what either of us are here to do. This is your job.' But Republicans tried to use the first hearing to undermine the testimony of both Taylor and Kent, repeatedly saying that they had no first hand knowledge of what President Trump was doing. 'Not only no conversations with the President of the United States about Ukraine, you've not had any contact with the President,' said Rep. Mike Turner (R-OH). 'Correct?' In a back and forth with Rep. Jim Jordan (R-OH), Taylor tried to keep a smile on his face as Jordan described Taylor as the supposedly prime witness for Democrats out to get President Trump. 'I don't consider myself a star witness for anything,' Taylor said. 'They do,' Jordan said of Democrats. While Ambassador Taylor dominated most of the headlines, Kent also provided some news, as he made clear that he felt the naming of Hunter Biden - the son of the former Vice President - to the board of a Ukrainian energy company, was a red flag which needed to be watched. But under questioning, Kent said he never found any evidence that it led to corruption - or anything illegal involving the younger Biden. Both Kent and Taylor raised questions about the President's lawyer, Rudy Giuliani, as Taylor frowned on what he described as an 'irregular' diplomatic back channel in Ukraine led by Giuliani. 'What interest do you believe he was promoting?' asked Rep. Val Demings (D-FL). 'I believe he was looking to dig up political dirt against a potential rival in the next election cycle,” Kent said. “I agree with Mr. Kent,” Taylor added, as the two officials reinforced the suspicions of Democrats that Giuliani was leading an effort which not only unseated the U.S. Ambassador, but led to the President pressing Ukraine for investigations of the Bidens, and of Ukraine interference in the 2016 elections. Asked about the question of Ukraine interference, Kent said there was 'no factual basis,' pointing the finger directly at Russia - as U.S. Intelligence agencies have done. There likely will be more discussion of Giuliani's role in Ukraine in the next hearing on Friday, when lawmakers hear from the ousted U.S. Ambassador Marie Yovanovitch. Kent testified there was a campaign of 'slander' against Yovanovitch, which began March 20, 2018.