Speaker Nancy Pelosi has chosen GOP Rep. Liz Cheney to join the Democrat-led investigation of the Jan. 6 Capitol attack, a rare cross-aisle elevation of one of Donald Trump's most prominent conservative critics.

The select committee on the insurrection will be led by Rep. Bennie Thompson (D-Miss.), who had previously crafted a bipartisan plan to establish an outside commission to lead the probe into the Jan. 6 violence. After Senate Republicans blocked the investigation, Pelosi and her Democrats established their own panel, which won just two Republicans on the floor on Wednesday.

Cheney, one of only two GOP votes for the select panel, has already seen her leadership credentials revoked after she publicly blamed Trump for inciting violence at the Capitol. Now, she could face more repercussions for accepting Pelosi’s appointment, with House Minority Leader Kevin McCarthy privately warning some GOP members that they could lose their committee assignments if they serve on the panel at Pelosi’s request, according to multiple Republican sources.

McCarthy said Thursday he is "not making any threats" about committee placement but added that he knows of no cases where a Republican “would get their assignments from the speaker."

“I was shocked that she would accept something from Speaker Pelosi,” he said of Cheney, adding she might be closer to Pelosi “than us.”

Cheney was unfazed following a meeting in Pelosi's office with the other select panel members. She signaled she had not talked with McCarthy or been told she would lose her committee assignment.

"It’s very clear to me, as I’ve said, my oath and my duty is above partisanship and I expect Leader McCarthy to have the same view,” she said.

Thompson declined to say how deeply his panel would parse Trump's role in the siege until the "parameters" of the investigation are set, though he's left the door open to seeking testimony from the former president, as well as McCarthy. Democrats have indicated that they will also examine the security shortfalls that were exposed by scores of protesters mobbing the Capitol that day. The panel's first hearing, not yet scheduled, will be with members of the Capitol Police, who would "testify about their experiences" defending the complex on Jan. 6.

But many lawmakers in both parties believe that intense scrutiny of Trump is inevitable as the panel digs into the root causes of the violence — and Democrats say Cheney's presence is a signal of how serious they plan to get.

"We need to figure out who organized the violence on Jan. 6. How did they organize it, and why did they organize it?" said Rep. Jamie Raskin (D-Md.), outlining the aims of the investigation.

House Intelligence Committee Chair Adam Schiff (D-Calif.) indicated existing investigations on Jan. 6 would continue but added that "there needs to be one committee whose focus is solely on this matter and compiling the comprehensive and authoritative report."

Many of Pelosi’s eight picks to the panel, which she announced Thursday, have experience investigating Trump during his presidency. Raskin led Democrats during Trump's second impeachment trial in response to the Jan. 6 attacks. Schiff served as lead impeachment manager when Democrats impeached Trump for the first time in 2019. And House Administration Committee Chair Zoe Lofgren (D-Calif.), also on the select panel, is a former impeachment manager too.

The additional select panel picks were Reps. Pete Aguilar (D-Calif.), a member of Pelosi’s leadership team, and a pair of Democrats with national security backgrounds: Reps. Stephanie Murphy of Florida and Elaine Luria of Virginia.

But the most notable name on Pelosi’s committee list is Cheney, who accepted a spot from the speaker by phone Thursday morning, according to a person familiar with the call. Many Democrats privately had hoped Pelosi would appoint the conservative Trump antagonist, in part to help mitigate the partisan rancor that's almost certain to result as the committee's investigation moves ahead.

"We are very honored and proud she has agreed to serve on the committee," Pelosi said at a press conference alongside her other Democratic picks. Cheney did not attend the press conference.

Several Republican lawmakers declined to weigh in on the Cheney pick, with many of them saying they were waiting for McCarthy to reveal his own plans and others saying they are generally wary of their party's fraught internal dynamics over Jan. 6. A group of pro-Trump GOP members has actively started to downplay the violence of the attack on Congress, including a few seeking seats on the select panel.

When asked about his response to Cheney's appointment, GOP Rep. Kelly Armstrong (R-N.D.) said: “Whatever the opposite of surprised is.”

McCarthy is already urging his GOP conference to stay far away from the panel’s work, underscored by his warning that he could strip the committee assignments of any Republican who accepted a Pelosi appointment. they choose to participate. Asked about McCarthy’s threat, Pelosi dismissed the question: “I’m not talking about him," she told reporters. "Go ask him about what he says.”

If McCarthy does try to yank Cheney from her committees, he'd be doing so without a green light from the top Republican on one of her panels.

“I don’t think any Republican member should participate in this Democrat controlled ‘Sham Theater,’” said Rep. Mike Rogers of Alabama, the House Armed Services Committee's ranking member. “But that is just my position, any member has a right to do whatever they want to do, regardless of whether it is productive or not.”

The other Republican who voted Wednesday to create the select committee, Illinois Rep. Adam Kinzinger, dismissed McCarthy's attempt to scare off Republicans who might accept a Pelosi offer to serve.

"Who gives a shit?" Kinzinger replied Thursday morning, confirming the warning from the California Republican. After Cheney was given a seat by Pelosi, Kinzinger tweeted a cheer: "Fantastic news!"

“I do think the threat of removing committees is ironic, because you won't go after the space lasers and white supremacist people but those who tell the truth,” Kinzinger added of McCarthy’s indication he would strip committee assignments from any members picked by Pelosi to serve on the panel.

Kinzinger's references to "space lasers" and "white supremacist people" are nods to Reps. Marjorie Taylor Greene (R-Ga.) and Paul Gosar (R-Ariz.), respectively. Greene lost her own committee assignments following a string of incendiary remarks, including a baseless conspiracy theory regarding wildfires and lasers, while Gosar spoke at a conference organized by a prominent white nationalist earlier this year.

"What happened on January 6th can never happen again," Cheney said in a statement confirming she would accept Pelosi's offer. "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 non-partisan manner."

McCarthy on Thursday declined to say whether he will make recommendations for GOP members to sit on the Democrat-led committee, and Pelosi indicated Thursday she could move ahead without any of his choices.

"We hope that they would choose them expeditiously," Pelosi said of McCarthy's picks for the panel. But if he doesn't, Pelosi said: "Well, we have a quorum."

But the California Republican's closed-door warning delivered Wednesday to several of his conference members suggests that he's preparing to do what he can to undercut the Jan. 6 committee's work.

That warning was first reported by Punchbowl News.

Olivia Beavers contributed to this report.