WASHINGTON — A career Justice Department prosecutor who quit the case against President Trump’s friend Roger J. Stone Jr. after political appointees intervened to seek a more lenient sentence has agreed to testify under subpoena next week before the House Judiciary Committee.
House Democrats issued subpoenas on Tuesday to the prosecutor, Aaron S.J. Zelinsky, along with a second Justice Department official, John W. Elias, who has also agreed to testify in public on June 24 about politicization under Attorney General William P. Barr — setting up a potential fight with the department about what they will be permitted to say.
Mr. Elias is a career official in the Justice Department’s antitrust division, which opened an inquiry into a fuel efficiency deal between major automakers and the state of California; congressional Democrats have called the scrutiny politically motivated.
The chairman of the Judiciary Committee, Representative Jerrold Nadler, Democrat of New York, said in a statement that Mr. Barr has refused to testify himself, so the committee was moving forward with oversight of his actions without him.
“The attorney general — who cites his busy schedule as a basis for refusing to appear before the House Judiciary Committee but has made time for multiple television interviews — may have abdicated his responsibility to Congress, but the brave men and women of our civil service have not,” Mr. Nadler said. “The committee welcomes the testimony of current and former department officials who will speak to the lasting damage the president and the attorney general have inflicted on the Department of Justice.”
Kerri Kupec, a Justice Department spokeswoman, declined to comment.
The ability of lower-level officials to testify about internal executive branch matters without permission can be subject to dispute. The executive branch sometimes claims that such matters are privileged. Still, it has limited ability to block officials who have been subpoenaed by Congress and who want to comply with those legal demands to testify.
A third expected witness at the June 24 hearing is Donald Ayer, who served as deputy attorney general in the first George Bush administration when Mr. Barr led the department’s Office of Legal Counsel in 1989 and 1990, before Mr. Barr succeeded him as deputy attorney general and then ascended to his first stint as attorney general.
Mr. Ayer has been a frequent critic of Mr. Barr’s conduct, including portraying the attorney general’s interventions in the criminal prosecutions of Mr. Stone and Michael T. Flynn, Mr. Trump’s former national security adviser.
Republicans on the Judiciary Committee can invite a witness of their own but have not selected one, according to a committee aide.
Mr. Zelinsky, an assistant United States attorney in Maryland, had been a member of the office of Robert S. Mueller III, the special counsel appointed to lead the investigation into whether Trump campaign officials coordinated with the Russian government in its 2016 election interference operation. He continued to handle the case against Mr. Stone, which spun off that inquiry.
In February, when Mr. Stone was due to be sentenced for crimes related to trying to sabotage a separate congressional inquiry into the Russian matter in order to protect Mr. Trump, Mr. Zelinsky was one of four career prosecutors who abruptly withdrew from the case when the Justice Department revised its recommendation for Mr. Stone’s sentence.
The department had just suggested a sentence seven to nine years, in line with standard guidelines. But Mr. Trump then attacked the recommendation on Twitter as unfair, and department political appointees, overruling career prosecutors, submitted a revised recommendation seeking greater leniency.
A Federal District Court judge ultimately sentenced Mr. Stone to slightly more than three years in prison. But the sequence set off an uproar over whether Mr. Barr was giving special treatment to a presidential ally. It prompted Mr. Barr to say in an interview that he wanted Mr. Trump to stop commenting on cases in public, saying such commentary made “it impossible for me to do my job and to assure the courts and the prosecutors in the department that we’re doing our work with integrity.”
Robert S. Litt, a former general counsel for the Office of the Director of National Intelligence, who is representing Mr. Zelinsky, said his client “has received a subpoena and he will comply with the subpoena to the extent appropriate.”
He declined to say what Mr. Zelinsky would discuss. A Democratic aide said that Mr. Zelinsky would testify about what happened in the sentencing of Mr. Stone and that Mr. Elias would testify about purportedly improperly motivated activity by the Antitrust Division. The aide provided no further details about Mr. Elias’s expected disclosures.
But Mr. Elias’s service in the Antitrust Division coincides with an inquiry into a deal struck by four major automakers with the State of California. Under the deal, Ford, Honda, Volkswagen and BMW would voluntarily continue to improve fuel efficiency and reduce emissions on new cars, despite the Trump administration’s rollback of federal standards.
Mr. Trump attacked the deal on Twitter, and congressional Democrats accused the Justice Department of starting the antitrust inquiry for political reasons. The Justice Department dropped the inquiry earlier this year, but not before the prospect of legal scrutiny scared off Mercedes-Benz, which was said to have been close to joining the deal with California.
Katie Benner contributed reporting.