Sondland testified for more than nine hours on Capitol Hill Thursday, as Mick Mulvaney, the acting White House chief of staff, told reporters that the president had cut off military aid to Ukraine in part to pressure Ukrainian officials to probe Democrats, and an unsubstantiated theory that it was Ukraine, not Russia, that hacked the Democratic National Committee in the 2016 election.
Asked about the comments from Mulvaney, Sondland said that the arrangement, if described accurately, would be improper, but did not say whether he believed it to be illegal, according to sources familiar with his remarks.
Mulvaney tried to walk back his White House comments in a statement Thursday denying what he had said in the press briefing room constituted a quid pro quo, though not walking back any of those original remarks. And Democrats seized on his initial remarks.
"You can't exert pressure on a foreign government to do anything for your election benefit," Rep. Raka Krishnamoorthi, D-Illionis, told reporters.
Republicans, including some who were startled by Mulvaney's initial comments, quickly pointed to his follow up statement, and insisted he had misspoken.
"Based on my conversations, not only with Mick Mulvaney but others, in addition to the five witnesses we've had, I have zero concern - zero concern - that aid was withheld for any political reason," Rep. Mark Meadows, R-N.C., said Friday. "I don't think he's incorrect, I know he's incorrect."
Sondland, who despite his official title, played a large role in the administration's Ukraine policy and events at the center of Democrats' impeachment inquiry, told investigators Trump had directed him and others to work with his personal lawyer Rudy Giuliani to push Ukraine to conduct investigations, but that he wasn't aware of the efforts and their motives, according to his opening statement obtained by ABC News.
He told investigators that he and other senior administration officials disagreed with Trump's request to work with Giuliani, but said that he felt he could not ignore a directive from the president.
"Our view was that the men and women of the State Department, not the President’s personal lawyer, should take responsibility for all aspects of U.S. foreign policy towards Ukraine," he told lawmakers, according to his opening statement.
Other diplomats and former administration officials who have appeared before Congress have suggested that Sondland was a key player in efforts to push Ukraine to conduct investigations outside of normal diplomatic channels.
Sondland told lawmakers he was not aware of a connection between the push to investigate Ukrainian energy company Burisma and the Biden family, and did not know initially that former Vice President Joe Biden's son Hunter served on the company board - a claim that some lawmakers were skepitcal of, in light of Giuliani's many social media posts and interviews on the subject at the same time.
"I read the opening statement, and everything that followed, as Mr. Sondland engaging in a C.Y.A. operation for himself," Rep. Gerry Connolly, D-Va., said.
"Giuliani made no secret of what he was doing," he added, referencing an appearance Giuliani made on Fox News in April.
House investigators have heard from other witnesses who have raised questions about Sondland's role in the administration's Ukraine policy and work with Giuliani and other senior officials.
Fiona Hill, the National Security Council’s former senior director for European and Russian affairs, told House impeachment investigators that she believed Sondland was a potential national security risk, given his inexperience and extensive use of a personal cell phone for official diplomatic businesses, sources familiar with her testimony earlier this week told ABC News.