William Brockenbrough Taylor Jr., West Point class of ’69, Vietnam War veteran, Bronze Star recipient, career public servant, possesses a basso profundo voice and a patrician bearing that lent gravitas to his star turn Wednesday in the impeachment inquiry into whether President Trump abused his office.

Taylor’s lawyerly and television-ready delivery as a leadoff witness in the public phase of the inquiry put a face to the alarm of top State Department officials over the apparent conditioning of U.S. military aid on investigations of Trump’s political rivals.

Over about five hours, the acting U.S. ambassador to Ukraine remained mostly unflappable.

“I don’t consider myself a star witness for anything,” Taylor said under questioning by Rep. Jim Jordan (R-Ohio) that implied Taylor was doing Democrats’ bidding.

“They do,” Jordan shot back, referring to the majority Democrats.

“I think I was clear that I’m not here to take any particular side or the other,” Taylor replied evenly.

Taylor has emerged as a singular engine in the impeachment probe, delivering two rounds of testimony in three weeks that advanced the narrative and pointed at Trump’s involvement in the alleged quid pro quo.

Until Wednesday, the veteran diplomat had little public profile. But by the end of the hearing, Taylor’s low-key sincerity had made him a cult figure among observers online — the subject of memes, adoring tweets and articles that compared his vocal timbre to that of broadcaster Walter Cronkite.

For Republicans, Taylor also offered an opening: an opportunity to undermine the impeachment inquiry as a “sham” fed by secondhand or uncorroborated information. GOP lawmakers repeatedly noted that Taylor was not a party to the phone call between Trump and Ukrainian President Volodymyr Zelensky that is at the heart of the inquiry, and that he had not spoken directly with Trump.

Republicans also sought to question the loyalty and motives of Taylor and fellow State Department witness George Kent, as Rep. Devin Nunes (R-Calif.) did by implication at the start of the House Intelligence Committee hearing.

Nunes sarcastically congratulated the witnesses for passing Democrats’ “star chamber audition” to testify publicly, and said he wanted to remind listeners of “the immense damage a politicized bureaucracy has done to Americans’ faith” in government.

“Elements of the civil service have decided that they, not the president, are really in charge,” Nunes said, as Taylor looked on impassively.

For Democrats, Taylor is the face of selfless public service, someone whose background and demeanor make a charge of partisan skulduggery hard to stick.

He also provided the one big revelation of the first day of public hearings: a description of a phone call in which he said Trump spoke to another diplomat and checked on the status of the investigations he had urged Ukraine to pursue.

But Taylor did not help Democrats in one key respect: He repeatedly said he has no information to suggest that Ukrainian officials were aware early on that crucial military aid had been put on ice.

Taylor, 72, who was called out of retirement to take the Kyiv post in June, appeared wary of questions from lawmakers of both parties that called for speculation or sought to draw him away from a just-the-facts recitation.

He mostly kept his answers short: a crisp “yes, sir,” or “I don’t believe so, ma’am.”

Asked for his views after Kent had said that Trump’s July 25 phone call was troubling, Taylor replied only: “I agree.”

Illinois Democratic Rep. Raja Krishnamoorthi’s request for elaboration elicited one further point. Taylor said he found Trump’s disparaging remarks about his predecessor, Ambassador Marie Yovanovitch, “a cause for concern.”

While Taylor did not interact with Trump, he has served as a crucial witness because he was in touch with diplomats and others working on both the official and unofficial aspects of U.S. policy toward Ukraine and its new government.

The top U.S. envoy to Ukraine said that when he arrived in that country in June he “found a confusing and unusual arrangement for making U.S. policy toward Ukraine.”

His detailed account of what he called a “highly irregular” parallel Ukraine policy gave Democrats the clearest road map for an argument that Trump had abused his office by making an improper demand of a foreign leader.

Retracing his closed-door testimony late last month, Taylor described how the traditional State Department-led foreign policy structure became increasingly sidelined in the weeks after he took the top job in Kyiv.

A careful note-taker, Taylor kept logs of his discussions with other diplomats last summer, as his concern grew over what he saw as a hijacking of U.S. policy toward a vulnerable ally.

He was prepared to quit in August, after just two months, over what he saw as a shift away from strong support for Ukraine, Taylor said.

“There appeared to be two channels of U.S. policymaking and implementation, one regular and one highly irregular,” Taylor told the impeachment proceedings held in public for the first time.

Rep. John Ratcliffe (R-Tex.) asked if either Taylor or Kent would identify an impeachable offense by Trump in the July 25 phone call, then cut Taylor off as his time for questions dwindled. House Intelligence Committee Chairman Adam B. Schiff (D-Calif.) intervened, and Taylor cracked a smile.

“Mr. Ratcliffe, I would just like to say that I’m not here . . . to decide about impeachment. That is not what either of us are here to do. This is your job,” Taylor said.

Ratcliffe resumed by telling Schiff to “restore time to the clock to one minute.”

“No,” Schiff said, “but you may continue at 22 seconds.” The audience chuckled quietly, and Taylor suppressed another smile.

Later, Taylor defused moments of good-television tension that some Republicans appeared to try to stoke.

“Since you learned it from others, you could be wrong, correct?” Rep. Michael R. Turner (R-Ohio) asked of Taylor’s testimony. “. . . They could be wrong, or they could be mistaken, or they could have heard it incorrectly, right, Ambassador Taylor?”

“People make mistakes,” Taylor said agreeably, as he propped his elbow on the desk.

Taylor told lawmakers in his opening statement that he has been appointed to government posts by every president since Ronald Reagan, including Trump.

He said he stands by his earlier characterization that “withholding security assistance in exchange for help with a domestic political campaign in the United States would be ‘crazy.’ ”

He provided new information that Democrats said bolsters a case that Trump applied improper pressure to Zelensky, who was elected on an anti-corruption platform in April. He described how a member of his staff at the U.S. Embassy in Kyiv had overheard Trump speaking with U.S. Ambassador to the European Union Gordon Sondland on July 26. That was the day after Trump told Zelensky in their phone conversation that he wanted the “favor” of Ukrainian investigations into 2020 Democratic presidential contender Joe Biden’s son Hunter, who had served on the board of a Ukrainian gas company.

Sondland had called Trump on a mobile phone from a Kyiv restaurant on July 26 to update him on meetings he was having in the city, Taylor said.

The aide heard Trump through the phone asking about “the investigations,” to which Sondland said the Ukrainians were ready to move forward, according to Taylor.

Taylor said that after the call, the aide asked Sondland what Trump thought about Ukraine and Sondland had replied that Trump cares “more about the investigations of Biden” that the president’s personal attorney Rudolph W. Giuliani “was pressing for.”

Taylor said he had only learned of this conversation last week, so had not included it in a closed-door deposition on Oct. 22.

Rep. Sean Patrick Maloney (D-N.Y.) walked Taylor through his U.S. Military Academy and military career, including that he was No. 5 in a class of 800 and took a tough infantry assignment in Vietnam, in an apparent effort to embarrass Republicans.

Taylor himself looked embarrassed, though proud, and then appeared relieved when the questioning turned to his discussions with a Ukrainian military commander he said was eager and grateful for the aid in question.

Before the hearing began, Trump tweeted “NEVER TRUMPERS” in apparent reference to government employees Taylor and Kent. During the hearing, Trump retweeted Republican lawmakers who mocked the “star witness” as a know-nothing.

“Ambassador Taylor, are you a ‘never-Trumper?’ ” asked Rep. Eric Swalwell (D-Calif.)

“No, sir,” Taylor replied.