WASHINGTON — As a member of Congress, Mike Pompeo drove the Republican inquiry into the killing of a United States ambassador in Benghazi, Libya, and made clear there was no place for politics in American diplomacy. Nor, he said, would he tolerate “dithering” by an Obama administration State Department that he called “deeply obstructive of getting the American people the facts that they needed.”
Now, as secretary of state, Mr. Pompeo is facing a political crisis that directly challenges his leadership of the department he once excoriated. He is accused by House Democrats of blocking their impeachment inquiry by resisting the release of information to Congress that may shed light on the Trump administration’s shadow foreign policy with Ukraine.
And career diplomats, some of whom blame the Trump administration for dismembering the Foreign Service and undercutting American diplomacy, are expected to be among the first witnesses telling their stories to Congress during its inquiry.
“In many ways this seems to be a situation where he’s reaping what he sowed,” said Derek Chollet, the executive vice president of the German Marshall Fund, who served in both the State and Defense Departments under President Barack Obama.
During the Benghazi hearings in 2016, Mr. Pompeo bombarded Secretary of State Hillary Clinton with questions about whether the State Department had failed to put adequate security on the ground, leading to the death of an American ambassador. Now Mr. Pompeo is being asked whether his State Department was part of an effort to pressure Ukraine to investigate former Vice President Joseph R. Biden Jr.
The details are different, but lawmakers in both cases accused the State Department of obstruction and not supporting its diplomats.
With the tables turned, the House Foreign Affairs Committee is expected on Thursday to query Kurt D. Volker, a longtime diplomat, former ambassador to NATO and, until last week, the Trump administration’s special envoy for Ukraine.
Mr. Volker is the man who put Mr. Trump’s personal lawyer, Rudolph W. Giuliani, in touch with the new government in Kiev, though he appeared to have deep reservations about how Ukraine policy was veering off course. His testimony is expected to be followed over the coming days by that of Marie L. Yovanovitch, who was recalled early as the American ambassador to Ukraine and dismissed by Mr. Trump as “bad news,” someone he promised would “go through some things.”
Both will be asked whether they had evidence that Mr. Trump or his representatives were dangling American support — and suspending congressionally approved military assistance — to get political dirt from the Ukrainian government to undercut the presidential campaign of Mr. Biden.
Mr. Pompeo has often said that the Trump administration has not been tested by a true foreign crisis and that sooner or later one was coming. Now he is caught in the middle of a domestic one. He will be pressed to explain what he knew — after acknowledging that he listened in on a July 25 phone call between Mr. Trump and the newly elected president of Ukraine, Volodymyr Zelensky — and how he reacted when he heard his boss seek political help.
“I was on the phone call,” he said Wednesday, but ignored a question about what he thought about Mr. Trump’s requests.
That admission was a marked change. In interviews in recent weeks, Mr. Pompeo repeatedly evaded questions about the content of the call between the two presidents, and never volunteered that he had listened in.
In an interview on Sept. 22, days before the White House released a transcript of the call, Mr. Pompeo suggested that he was unaware of the details, telling Martha Raddatz of ABC that he had not seen the whistle-blower report and then describing American policy toward Ukraine in traditional terms, without reference to the favors Mr. Trump sought.
The Benghazi hearings that first brought national attention to Mr. Pompeo, then a conservative congressman from Kansas, investigated systematic security failings after four Americans, including Ambassador J. Christopher Stevens, were killed in an attack on a diplomatic outpost and a nearby C.I.A. annex in 2012. The two-year congressional inquiry — one of the most bitterly partisan in history — concluded that the State Department and the C.I.A. did not appreciate the high security risk in Benghazi, but found no evidence that Mrs. Clinton was directly to blame.
Like the Benghazi hearings, the impeachment proceedings, opened last week by House Democrats, are as immersed in diplomacy as they are in political intrigue. In recent days Mr. Pompeo’s role in the Ukraine chain of events has become increasingly clearer — and ever closer to the center of the controversy.
His presence on the call with Mr. Zelensky was unusual, though not improper: Past secretaries of state have occasionally joined such calls, and often sit in on face-to-face meetings between presidents and foreign leaders.
But the questions are swirling about what role Mr. Pompeo may have played, if any, in Mr. Giuliani’s outreach campaign to top Ukrainian government officials. The effort bypassed career State Department diplomats, and Mr. Pompeo is nothing if not territorial — meaning he most likely would have objected to such dealings unless he was under instructions to allow them to proceed.
Then there is the question of the recall of Ms. Yovanovitch back to Washington after she was accused of being a disloyal envoy and was disparaged by the president’s son Donald Trump Jr.
The Foreign Affairs Committee is interested, and American diplomats, who declined to be named, say that Foreign Service officers have been in contact with the committee’s staff. A three-time ambassador, Ms. Yovanovitch has inspired considerable loyalty among her colleagues, many of whom seem ready to stand up in her defense.
Mr. Pompeo accused the House Democrats this week of directly contacting State Department officials and said they had been urged not to report the outreach.
That led to a sharp retort from three committee chairmen — Eliot L. Engel of the Foreign Affairs Committee, Adam B. Schiff of the Intelligence Committee and Elijah E. Cummings of the Oversight and Reform Committee — reminding Mr. Pompeo that it is a crime to obstruct a congressional inquiry “by threats or force, or by any threatening letter or communication.”
For his part, Mr. Pompeo has cast the State Department’s actions as above reproach.
“To the best of my knowledge, so from what I’ve seen so far, each of the actions that were undertaken by State Department officials was entirely appropriate,” Mr. Pompeo said on Sept. 26 in New York.
On Wednesday, he said American policy toward Ukraine would remain focused on pushing back against Russia, strengthening ties between Washington and Kiev, and rooting out corruption in Ukraine.
“It’s what the State Department officials that I’ve had the privilege to lead have been engaged in,” Mr. Pompeo said on Wednesday while on a diplomatic visit to Rome, “and it’s what we will continue to do, even while all this noise is going on.”
Officials close to Mr. Pompeo have described him as angry over Mr. Giuliani’s pressure campaign for the Ukrainian government to open an investigation into whether Mr. Biden, as vice president, had forced out a top prosecutor in order to shut down an inquiry that might have implicated his son Hunter Biden.
But caught between his loyalty to the president and his instinct to defend the State Department, Mr. Pompeo has never discussed the issue directly.
Mr. Pompeo’s supporters also say he recalled Ms. Yovanovitch out of concern for her safety as anger mounted against her in Kiev, where she had also criticized government corruption under the former Ukrainian president, Petro O. Poroshenko.
In neither case, however, did Mr. Pompeo speak out publicly to defend his diplomat or protect the State Department’s well-established turf in foreign affairs.
Not until Tuesday, in the middle of a visit to the Italian president’s official residence, did Mr. Pompeo come out swinging. But his broadside was aimed at the House Democrats who have demanded sworn testimony from Ms. Yovanovitch, Mr. Volker and three other State Department staff members.
Those depositions, initially scheduled to take place less than a week after they were compelled, amounted to “an attempt to intimidate, bully and treat improperly the distinguished professionals of the Department of State,” Mr. Pompeo wrote in a letter to Mr. Engel, Democrat of New York.
The Democrats now see Mr. Pompeo as another potential witness in the investigation and said that any attempts to block testimony or State Department documents “may infer that he is trying to cover up illicit activity and misconduct.”
“This would be a blatant cover-up and a clear abuse of power,” they said.
It was the latest move in an inquiry that promises to be part investigation, part political theater — just like the Benghazi hearings.