Speaker Nancy Pelosi on Thursday named Representative Liz Cheney of Wyoming to a newly created special committee to investigate the Jan. 6 riot at the Capitol, choosing a Republican who has blamed former President Donald J. Trump for fomenting the assault to help conduct an inquiry that the rest of her party has fought to block at every turn.
The appointment drew an angry response from the top House Republican, who suggested that Ms. Cheney — already ousted from party leadership for her insistence on calling out Mr. Trump’s election lies — could face fresh retribution for agreeing to help Democrats investigate the deadliest attack on Congress in centuries.
The reaction was the latest bid by Republican leaders to turn public attention away from the assault on the Capitol and punish those who insist on scrutinizing the riot. It came as a fuller picture is emerging of how violent extremists, taking their cues from Mr. Trump, infiltrated the seat of American democracy just as Congress was meeting to validate President Biden’s election.
A New York Times visual investigation published this week revealed in vivid detail how members of extremist groups incited others to riot and assault police officers, and underscored how the former president’s words resonated with the mob in real time as it staged the attack.
Representative Kevin McCarthy, Republican of California and the minority leader, responded angrily to Ms. Cheney’s decision to accept the post, calling it “shocking” and implying that she could lose her seat on the Armed Services Committee as payback.
“I don’t know in history where someone would get their committee assignments from the speaker and then expect to get them from the conference as well,” Mr. McCarthy said.
Should he follow through with the threat, it would be a striking move for Mr. McCarthy, who has declined to penalize Republicans who have made anti-Semitic comments, called for the imprisoning of their Democratic colleagues or spread false conspiracy theories about the origins of the assault on the Capitol.
It would also be the second time in two months that Mr. McCarthy punished Ms. Cheney for insisting that Congress should scrutinize the attack and Mr. Trump’s role in spreading the falsehoods about voting fraud that inspired it. In May, Mr. McCarthy led the charge to oust Ms. Cheney from her post as the No. 3 House Republican, saying her criticisms of Mr. Trump and efforts to sound the alarm about the riot were undermining party unity and hurting its chances of reclaiming the House in the 2022 elections.
“My oath, my duty is to the Constitution, and that will always be above politics,” Ms. Cheney told reporters in the Capitol on Thursday, appearing alongside the seven Democrats Ms. Pelosi had selected for the 13-member panel.
According to its rules, Mr. McCarthy has the right to offer five recommendations for Republican members, but he declined on Thursday to say whether he would do so.
The select committee was established at Ms. Pelosi’s behest after Senate Republicans blocked the formation of a bipartisan commission to scrutinize the riot. It will investigate what its organizing resolution calls “the facts, circumstances and causes relating to the Jan. 6, 2021, domestic terrorist attack.” The committee is also charged with reporting its findings, conclusions and recommendations for preventing such attacks in the future.
The panel’s creation comes as some far-right House Republicans have stepped up their efforts to deny or distort the riot, including by spreading misinformation about it. They have sought to portray it as a mostly peaceful event and voted against honoring police officers who responded. One House Republican accused a U.S. Capitol Police officer of “lying in wait” to carry out an “execution” of a rioter. Another compared the events of that day to a “normal tourist visit” to the Capitol. Still others have amplified the baseless theory that the F.B.I. was secretly behind the siege.
On Thursday, Mr. Trump amplified those narratives, releasing a one-sentence statement questioning the killing of Ashli Babbitt. Ms. Babbitt was shot as she tried to break into an area off the House floor where several lawmakers were taking cover, and her death has become a rallying cry of the far right.
In taking the unusual step of giving one of her seats on the panel to a member of the opposing party, Ms. Pelosi was making a tactical move that appeared intended to drive a wedge among Republicans while putting a veneer of bipartisanship on an investigation that most of them have already dismissed as politically motivated and one-sided.
The selection also all but ensures that Ms. Cheney, a prominent conservative from a storied Republican family, remains a high-profile voice countering her party’s attempts to downplay and deny the horrors of the attack, risking her political career to do so.
For weeks, Republican leaders have tried to silence and ostracize Ms. Cheney, but she has remained undeterred. On Thursday, said she was “honored” to serve on the committee.
“Those who are responsible for the attack need to be held accountable, and this select committee will fulfill that responsibility in a professional, expeditious and nonpartisan manner,” she said.
Ms. Pelosi called Ms. Cheney personally on Thursday morning to offer her the post, and Ms. Cheney accepted on the spot, according to aides to both lawmakers. The two had not spoken previously about the prospect, the aides said, although Ms. Pelosi had let it be known this week that she was weighing naming a Republican to her side of the panel.
Ms. Cheney’s selection was announced during Ms. Pelosi’s Thursday morning news conference, when she laid out a list of powerful lawmakers who would carry out the inquiry. The panel is to be led by Representative Bennie Thompson, a Mississippi Democrat who is the chairman of the Homeland Security Committee. It includes two other committee leaders, Representatives Adam B. Schiff of the Intelligence Committee and Zoe Lofgren of the Administration Committee, both of California.
Also included are Representative Jamie Raskin, Democrat of Maryland and the lead prosecutor in the impeachment case against Mr. Trump for “incitement of insurrection,” and Representative Pete Aguilar of California, a member of the party leadership. Ms. Pelosi also chose two moderate Democrats, Representative Elaine Luria of Virginia and Representative Stephanie Murphy of Florida, the leader of the centrist Blue Dog Coalition.
House Republicans voted on May 12 to oust Representative Liz Cheney of Wyoming from their leadership ranks for her refusal to stay quiet about President Donald J. Trump’s election lies.
- Backlash to Impeachment Vote: In January, Ms. Cheney issued a stinging statement announcing that she would vote to impeach Mr. Trump. In the statement, which drove a fissure through her party, she said that there had “never been a greater betrayal by a president of the United States” than Mr. Trump’s incitement of a mob that attacked the Capitol on Jan. 6. She was among 10 Republicans who voted to impeach him. A group of Mr. Trump’s most strident allies in the House called on her to resign from her leadership post.
- Leadership Challenge: In February, Ms. Cheney fended off a challenge to strip her of her leadership position in a secret ballot vote. Even as a majority of House Republicans opposed impeaching Mr. Trump, most were not prepared to punish one of their top leaders for doing so — at least not under a blanket of anonymity.
- Censure: Ms. Cheney also faced opposition from the Wyoming Republican Party, which censured her and demanded she resign. Ms. Cheney rejected those calls and urged Republicans to be “the party of truth.”
- New Challenge: Ms. Cheney continued her blunt condemnation of Mr. Trump and her party’s role in spreading the false election claims that inspired the Jan. 6 attack, prompting a new push to oust her from her leadership role. This time, the effort was backed by Representative Kevin McCarthy, the minority leader.
- Removal: Ms. Cheney framed her expulsion as a turning point for her party and declared in an extraordinary speech that she would not sit by quietly as Republicans abandoned the rule of law. She embraced her downfall and offered herself as a cautionary tale in what she is portraying as a battle for the soul of the Republican Party. The removal came by voice vote during a brief but raucous closed-door meeting in an auditorium on Capitol Hill.
- Impact and Analysis: What began as a battle over the party’s future after the violent end to the Trump presidency has collapsed into a one-sided pile-on by Team Trump against critics like Ms. Cheney, a scion of a storied Republican family. The episode, a remarkable takedown that reflected the party’s intolerance for dissent and unswerving fealty to the former president, has called attention to internal party divisions between more mainstream and conservative factions about how to win back the House in 2022.
- Successor: On May 14, House Republicans elected Representative Elise Stefanik of New York, a vocal defender of Mr. Trump, as their No. 3 leader. Ms. Stefanik pledged to maintain a focus “on unity” as conference chair, but she has also drawn criticism from some hard-right Republicans who have questioned her conservative bona fides.
Mr. Thompson pledged to deliver “a definitive accounting of the attack — an undertaking so vital to guarding against future attacks.”
“We have to get to the bottom of finding out all the things that went wrong on Jan. 6,” he said.
He also said the panel would hold a hearing in which “Capitol Police officers themselves could be able to testify about their experiences” during the attack.
Several congressional investigations into the assault are already underway, but none have a mandate to look comprehensively at the event similar to how fact-finding commissions scrutinized the Sept. 11, 2001, terrorist attacks; the bombing of Pearl Harbor in 1941; and the assassination of President John F. Kennedy in 1963.
The F.B.I. has arrested nearly 500 people involved in the Capitol breach and is pursuing potentially hundreds more. Two Senate panels carrying out a joint investigation into the riot produced a report outlining large-scale failures that contributed to the assault. And several inspectors general have begun their own inquiries, finding lapses and miscalculations around the most violent attack on the Capitol since the War of 1812.
But those inquiries, which have mostly focused on security failures, are no substitute for a select committee that can focus solely on investigating the attack and its root causes, Ms. Lofgren said.
“It’s not a substitute for finding out what happened here,” Ms. Lofgren said. “What caused a mob of Americans to think they were somehow supporting the Constitution when they tried to disrupt the constitutional process of counting the Electoral College votes? Who paid for it? How was it organized? We need to find that out to keep the country safe.”
The measure that created the panel was adopted on Wednesday over the opposition of nearly every Republican. Only Ms. Cheney and one other Republican, Representative Adam Kinzinger of Illinois, supported it.
“We cannot ignore what happened on January 6th; we cannot ignore what caused it,” Mr. Kinzinger wrote Thursday on Twitter, appending the hashtag “TheBigLie.” He pointed to the visual investigation The Times published on Wednesday, which provided the most complete picture to date of how supporters of Mr. Trump planned and carried out the deadly assault.
Mr. McCarthy faces a challenge in deciding whom to recommend for the panel. Republicans, many of whom initially called for a full investigation, have long since lost their appetite for scrutinizing the assault, following Mr. Trump’s lead.
Even without Mr. McCarthy’s appointments, however, the committee would have enough members to proceed with its work.
Mr. McCarthy initially denied on Thursday that he would penalize any Republican for accepting an appointment to the panel from Ms. Pelosi, saying he was “not making any threats” on the matter.
But he then appeared to do just that, saying that no Republican should expect to keep committee posts granted by the G.O.P. after accepting an appointment from the other party. He noted with displeasure that Ms. Cheney had not talked to him before taking Ms. Pelosi’s offer.
“Maybe she’s closer to her than us,” Mr. McCarthy said.