WASHINGTON — House Democrats’ feud with Attorney General William P. Barr boiled over on Thursday, as Speaker Nancy Pelosi accused the nation’s top law enforcement officer of lying to Congress and the Judiciary Committee threatened to hold him in contempt if he did not promptly hand over a complete version of Robert S. Mueller III’s report.
The escalation between the legislative and executive branches of government, a day after Mr. Barr mounted an aggressive self-defense in the Senate, was as abrupt and emotionally charged as any in decades.
The Justice Department had ignored a Wednesday deadline to provide an unredacted version of the report by Mr. Mueller, the special counsel, and the investigative materials used to compile it. Then, on Thursday morning, Mr. Barr failed to appear at a House hearing on Mr. Mueller’s investigation of Russian election interference, and possible obstruction of justice by President Trump, because of a dispute over who would be allowed to question the attorney general.
But it was a newly revealed letter from Mr. Mueller to the attorney general that most provoked Ms. Pelosi’s ire.
In the letter, the special counsel took Mr. Barr to task for the way that the attorney general had initially summarized his findings, leaving “public confusion about critical aspects of the results of our investigation.” That appeared to undercut Mr. Barr’s claims at a House hearing on April 9 that he was not aware of any such discontent.
“What is deadly serious about it is the attorney general of the United States of America was not telling the truth to the Congress of the United States,” Ms. Pelosi told reporters. “That’s a crime.”
The Justice Department and Republicans on Capitol Hill fired back; Kerri Kupec, a department spokeswoman, called Ms. Pelosi’s comments a “baseless attack” that was “reckless, irresponsible and false.”
Mr. Barr had offered his own defense on Wednesday, telling senators that his comments about not knowing the feelings of the special counsel’s office referred to the investigators — not Mr. Mueller himself.
The calls for Mr. Barr to be held in contempt of Congress stem not from Mr. Mueller’s letter or his refusal to appear in front of the committee on Thursday. Instead, they follow the Justice Department’s decision not to honor the House Judiciary Committee’s subpoena for Mr. Mueller’s report without redactions and all the evidence his investigators collected.
In a letter to lawmakers, the department said that sharing the information would put the integrity of its investigations at risk.
Democrats were not ready to accept that answer.
Convening in a nearly empty hearing room, the Judiciary Committee’s chairman, Representative Jerrold Nadler of New York, called on Republicans to join Democrats against an administration that he said was systematically thwarting the constitutional duty of Congress to conduct oversight of the executive branch.
Mostly, though, he trained his ire at the attorney general, who had objected to Mr. Nadler’s insistence that staff lawyers be allowed to ask questions at the hearing.
“We will have no choice but to move quickly to hold the attorney general in contempt if he stalls or fails to negotiate in good faith,” Mr. Nadler said. “But the attorney general must make a choice. Every one of us must make the same choice. That choice is now an obligation of our office.”
“The choice is simple: We can stand up to this president in defense of the country and the Constitution we love, or we can let the moment pass us by,” he said.
The practical challenge for Mr. Nadler and other House committee leaders — who had hoped to hold Mr. Trump accountable without formal impeachment proceedings — is to decide how to respond to an administration that has refused to cooperate with any of their investigations.
Mr. Nadler said he would give Mr. Barr “one or two more days” to produce Mr. Mueller’s entire report before initiating contempt proceedings. Committee Democrats were preparing to make the Justice Department a formal counteroffer to stave off another escalation of hostilities.
But with no cooperation in sight, House Democrats could soon have to choose from a handful of paths to raise the pressure.
Some lawmakers want to open an impeachment inquiry of Mr. Trump, effectively turning the House into a grand jury. That would give the legislative body clearer powers to command information from the executive branch, including secretive grand jury material.
In a private meeting with members of her leadership team, Ms. Pelosi called Mr. Barr a “lap dog” for Mr. Trump and an “enabler” of obstruction of justice, according to a congressional aide in the room. But she continued to hold her line against impeachment.
“Impeachment is too good for him,” she said of Mr. Trump, according to the aide.
A contempt proceeding, though not necessarily punitive, would put a mark on Mr. Barr’s record and could push the dispute into the courts. House Republicans chose that route in 2012 when they held Attorney General Eric H. Holder Jr. in contempt of Congress for failing to turn over internal Justice Department documents on a botched gunrunning investigation called Fast and Furious.
Democrats could begin the proceedings as soon as next week if they cannot budge Mr. Barr, but it would take at least months for the process to play out.
Democrats are also trying to secure testimony from Mr. Mueller. And it is unclear if Donald F. McGahn II, the former White House counsel whom the committee subpoenaed to testify this month, will show up.
Democrats are not alone in their unhappiness over how the nearly two-year special counsel investigation is coming to a close.
In a letter to Mr. Barr that was dated April 19 but released on Thursday, a top White House lawyer, Emmet T. Flood, complained that the special counsel had violated the regulations governing his appointment by failing to reach a prosecutorial decision on obstruction of justice. Mr. Flood described Mr. Mueller’s findings as a 182-page discussion of evidence that were “part ‘truth commission’ report and part law school exam paper.”
Echoing Mr. Trump’s complaints about the “deep state,” though couching them in legalese, Mr. Flood accused unnamed officials of “a campaign of illegal leaks” to damage the president. He saidJames B. Comey, the former F.B.I. director, who was not named in the letter, had talked to reporters about his encounters with Mr. Trump to engineer the appointment of a special counsel.
“That the head of our country’s top law enforcement agency has actually done so to the president of the United States should frighten every friend of individual liberty,” Mr. Flood wrote.
Mr. Flood cautioned the attorney general that despite choosing against exerting executive privilege over material contained in the report, the president maintained the right to conceal raw evidence collected by the special counsel and to block witnesses from appearing before Congress.
In the House Judiciary Committee hearing room on Thursday, where the panel convened for only about 10 minutes, there were some moments of levity, too. Before the hearing began, Representative Steve Cohen, Democrat of Tennessee, munched on Kentucky Fried Chicken on the dais as press cameras clicked.
Officially, Mr. Barr refused to show for the Judiciary Committee hearing because Democrats had insisted that he sit for questioning from Democratic and Republican staff lawyers. In a statement on Wednesday, Ms. Kupec called Democrats’ demands “unprecedented and unnecessary.” She said Mr. Barr would be happy to testify if Democrats would drop that demand.
Mr. Cohen was not having it. “Chicken Barr should have shown up today and answered questions,” he told reporters. “An attorney general who’s picked for his legal acumen and his abilities would not be fearful of attorneys questioning him for 30 minutes.”
Seeking to dramatize the attorney general’s absence, Democrats set out an empty chair with a name card for Mr. Barr and insisted it was their prerogative to decide how to run their hearings.
“The so-called attorney general is abrasive, evasive and unpersuasive,” said Representative Hakeem Jeffries of New York, the No. 5 House Democrat and a member of the Judiciary Committee. “He is a disgrace to the office that he currently holds.”
Representative Doug Collins of Georgia, the top Republican on the committee, lit into his Democratic colleagues for making “ludicrous” demands and accused Mr. Nadler of manufacturing a conflict instead of trying to get at the truth.
“The reason Bill Barr is not here today is because the Democrats decided they did not want him here today,” Mr. Collins said, his rapid-fire Georgia accent winding up in indignation.
When Republicans tried to prolong the brief session with parliamentary objections, Mr. Nadler gaveled out, cut the microphones and walked out of the hearing room.
Maggie Haberman contributed reporting.