The third day of public impeachment testimony grew heated Tuesday when Devin Nunes, the top Republican on the House Intelligence Committee, pressed Lt. Col. Alexander S. Vindman on conversations he had with an intelligence official about the now infamous July 25 phone call between President Donald Trump and Ukrainian President Volodymyr Zelenskiy.

Chairman Adam B. Schiff shut down the line of questioning, asserting that it was an attempt to disclose the identity of the whistleblower whose anonymous report sparked Democrats’ impeachment inquiry.

Vindman, a Ukraine expert at the National Security Council, testified that he spoke with two individuals outside the White House about the call, both U.S. government officials with the appropriate clearances and a need to know. Transcripts of Vindman’s closed-door testimony state that he does not know the identity of the whistleblower.

“Please stop. I want to make sure that there is no effort to out the whistleblower through these proceedings,” said Schiff, a California Democrat.

Vindman pushed back against Nunes, requesting that he call him lieutenant colonel instead of “Mr. Vindman.” He stated that, on the advice of his counsel, he would not answer questions related to the whistleblower or the intelligence community.

Nunes suggested that Vindman himself was a leaker or a source to the whistleblower, and that he might be declining to answer questions because he feels he is at risk of self-incrimination.

“You’re here to answer questions and you’re here under subpoena. So you can either answer the question or you can plead the Fifth,” Nunes.

Vindman’s lawyer backed up Schiff, who told the panel that the whistleblower has “statutory right to anonymity.” The lawyer said his client will “follow the ruling of the chair.”

Jennifer Williams, a national security aide to Vice President Mike Pence, likewise said she had not leaked information to the media.

Earlier in the hearing, Schiff asked Williams about a September phone call between Pence and Ukrainian officials, and she said she would provide an answer in a classified setting. Her attorney said the call had been deemed classified by Pence’s office.

July 25 call

Both Vindman and Williams listened in on the July 25 call and publicly substantiated the whistleblower’s complaints about that conversation.

Vindman told the committee that after hearing the call, “without hesitation, I knew I had to report this to the White House counsel.”

On that phone call, Trump asked Zelenskiy for a “favor”: investigating former Vice President Joe Biden and his son, Hunter, who sat on the board of Ukrainian gas company Burisma. The elder Biden is a top contender for the 2020 Democratic presidential nomination.

At the time, the Office of Management and Budget had a hold on military aid to Ukraine.

“It was improper for the president to demand an investigation into a political opponent,” Vindman said.

Williams, a State Department employee detailed to Pence’s office, said she thought the call was unusual “because, in contrast to other presidential calls I had observed, it involved discussion of what appeared to be a domestic political matter.”

Vindman, a decorated Iraq war veteran, said he reported the call “out of a sense of duty.”

“My intent,” Vindman said in his opening statement, “was to raise these concerns, because they had significant national security implications for our country.”

During questioning from Democratic counsel, Vindman explained details of the call and the White House transcript of it.

The document does not include the word “Burisma,” even though Vindman said he believes he heard Zelenskiy mention the company by name. The company name, he said, was in his notes.

Vindman said that during an official review process of the transcript, he attempted to include a mention of the company. That addition was never included. Vindman, though, said it was not “a significant omission,” and that the staff who prepared the transcript do their “best” and likely didn’t catch the name of the company.

Discrediting the witness

Intelligence committee Republicans during the hearing attempted to cast doubt on Vindman’s credibility.

Ohio Republican Jim Jordan quoted from the transcript of National Security Council Senior Director for Russia and Europe Tim Morrison’s deposition, in which Morrison said he had concerns about Vindman’s judgment and was concerned the military officer leaked information to the press.

Vindman called that charge “preposterous” and read aloud from a glowing performance review lauding his judgment and intellect.

Michael R. Turner, another Ohio Republican, noted a discrepancy in Vindman’s job description.

In Vindman’s submitted written testimony, he identifies himself as the National Security Council’s “principal advisor to the National Security Advisor and the President on Ukraine.”

Vindman said that when he delivered his verbal opening statement he “chose to ease back on that language,” adding that he didn’t want to “overstate” his role.

Republicans were also quick to point out a job offer Vindman received to be the Ukrainian defense minister. Vindman, who was born in Ukraine and speaks the language, said he dismissed the offer and notified his chain of command.

“I’m an American. I came here when I was a toddler. And I immediately dismissed these offers. I did not entertain them,” said Vindman, who was born in Ukraine.

Rep. Jim Himes, D-Conn., dug into the Republican line of questioning, saying they were an attempt to sow uncertainty about the witness’ loyalty to the U.S.

“The three minutes spent asking you about the offer made to make you the minister of defense, that may have come cloaked in a Brooks Brothers suit and in parliamentary language, but it was designed exclusively to give the right-wing media an opening to question your loyalties,” Himes said.

Himes highlighted Vindman’s extensive military service, asking the him about his service and uniform, including his Purple Heart and combat infantry badge.

“It’s what you stoop to when the indefensibility of your case requires that you attack a man who is wearing a Springfield Rifle on a field of blue above a Purple Heart,” Himes said.

In his opening statement, Vindman said hat he chose military service from a young age because of his family’s refugee history.

“I wanted to spend my life serving the nation that gave my family refuge from authoritarian oppression, and for the last twenty years it has been an honor to represent and protect this great country,” he told lawmakers.

As the committee wrapped up its questioning of Vindman and Williams, Nunes dismissed said the effort had failed to uncover evidence Trump committed crimes that would warrant removing him from office.

“The Democrats are no closer to impeachment than they were three years ago,” Nunes said.