David Holmes will testify in Thursday's impeachment hearings. He overheard a conversation between Trump and Gordon Sondland where the president sought to confirm investigations into the Bidens.
In a phone interview with Glenn Beck, the former mayor of New York revealed he fed Ukraine and Biden stories to reporter John Solomon, who was offered a job with Fox News in October.
Ambassador Gordon Sondland directly implicated Giuliani in the "quid pro quo" arrangement between Trump and Ukrainian President Volodymyr Zelenskiy.
Ahead of his testimony Wednesday, Ambassador Gordon Sondland received a lengthy public warning against committing perjury from a Fordham law professor who explained that even if pardoned by Trump, Sondland could still be prosecuted in New York state.
State Department official David Holmes told lawmakers that a "childhood friend" of the Ukrainian president told him that "someone named Giuliani" claimed he advised the U.S. vice president.
"These ambassadors were upset that the president somehow was going around them," Nunes told Fox News. "Well, tough. Tough."
In response to whether or not President Trump will throw his lawyer under the bus during the impeachment inquiry, the former New York mayor was confident in their relationship—and also his "insurance."
Testimony from key officials has thus far been damning for President Donald Trump and his aides who ran the White House's parallel Ukraine policy.
In shows earlier this week, the Fox News host vehemently denied having contact with Secretary of State Mike Pompeo or anyone else from the department.
Conway commented on Giuliani hiring lawyers to represent him on a mounting investigation into his contact with two men facing campaign finance violation charges, who connected him to Ukrainian officials.
Giuliani's tweet "establishes that Trump was not acting for the country," Conway said.
"My knowledge...about any involvement of Mr. Giuliani was in connection with a campaign against our ambassador to Ukraine," John Sullivan testified to lawmakers.
"As expected, the right-wing will impugn someone's character," Senator Mazie Hirono said.
The blunder caused many to mock the former mayor, although some were angered by the mistake too.
The former New York City mayor was acting in a personal capacity on behalf of President Donald Trump while pursuing Ukraine conspiracy theories.
Ambassador Taylor and others were "embarrassed as all get out" by the situation, Representative Jim Himes said.
George Conway, Kellyanne Conway's husband, mocked Trump's tweet Wednesday morning, comparing Trump's claims about military aid in Ukraine to HBO's The Sopranos.
"I feel like if Donald Trump and Rudy Giuliani were trying to speed up the impeachment process, they could not do any better. They're really outdoing themselves every day."
"The national security picture, the idea underlying principles of the constitution that are being undermined here, those are being overlooked," said former FBI special agent Asha Rangappa.
Gordon Sondland's testimony represented a sharp break from Trump, who heavily pushed for his personal attorney to be involved in diplomatic discussions with Ukraine against the wishes of top officials.
"Basically, the FBI thinks something bad...is up: That Giuliani is a conduit for pushing the agendas of foreign intelligence and/or foreign interests," former FBI special agent Asha Rangappa said.
Neal Katyal said President Donald Trump is trying to "run out the clock" by refusing to comply with subpoenas to turn over evidence and witnesses in the impeachment inquiry.
Senate Judiciary Chairman previously made similar remarks during former President Bill Clinton's impeachment hearing.
"I mean, giddy-up, let's do it," Stephanie Ruhle suggested.
"There are multiple levels of misconduct here and look, there were 12 people on that call that the president made to the Ukraine president," Representative Stephen Lynch said.
"We know you're not in custody (yet)," Conway, who is married to Trump's senior counselor Kellyanne Conway, tweeted.
Trump has defended Giuliani as a "very good attorney" and slammed reported investigations as "shameful."
"He doesn't try to do it covertly," Senator Kevin Cramer of North Dakota told CNN.
Hunter Biden stepped down from the board of a Chinese-backed private equity company and has vowed to cease all foreign work should his father, Joe Biden, be elected president in 2020.