Several Republicans who oppose creating a commission to investigate the Jan. 6 attack on the U.S. Capitol are more than lawmakers making a public policy decision — they are potential witnesses to what former president Donald Trump and his aides were saying and doing as the mob laid siege.

Their testimony could answer questions about Trump’s state of mind that day, how responsive he was to pleas for help and whether he blocked or delayed his administration’s response.

But if Republican leaders are successful in sinking the bill, their accounts of that day may never come to light.

Jamie Gorelick, a former member of the bipartisan commission that investigated the Sept. 11, 2001, terrorist attacks, said it was “exceedingly unusual” for potential witnesses to be the ones deciding whether there should be a commission.

“It is just the case that whenever you have a call for a commission, which of course is an extraordinary event, it is pretty likely that someone in the political structure is not going to want to have it,” said Gorelick, a partner at WilmerHale and a former Clinton administration Justice Department official. She called the current scenario “a more acute case than others in the past.”

Testimony about Trump’s actions that day could be politically problematic for Republicans if it showed Trump ignored requests for help or had a callous or indifferent attitude toward the violence at the Capitol. The former president remains the dominant figure in the party and GOP leaders, who are wary of crossing him, have said they want him involved in the midterm elections as Republicans seek to win the majority in both the House and Senate.

“What really happened that day — and everyone knows it — is that the president was not interested in doing anything as the country was under attack,” said one Republican aide who was in the Capitol as the rioters came and who spoke on the condition of anonymity because they were not authorized to publicly discuss the matter. “The commission could prove that.”

Trump issued a statement this week strongly opposing the commission, calling it a “Democrat trap.” He remains in touch with many of the Republican lawmakers who are potential witnesses.

Many Republicans declined to answer questions Thursday about whether lawmakers who spoke with Trump on Jan. 6 should provide more information on their conversations.

Some, such as Senate Minority Leader Mitch McConnell (R-Ky.), responded to reporters’ questions with silence as he entered his Capitol Hill office. McConnell did not speak to Trump on Jan. 6 but spoke repeatedly to Vice President Mike Pence, who was orchestrating much of the administration’s response from a secure location in the Capitol where he had been presiding over the certification of President Biden’s electoral victory.

McConnell did not call Trump, seeing it as a futile exercise, a person close to him said.

Others, such as Rep. Greg Pence (R-Ind.), the former vice president’s older brother, said it was too soon to say. During the attack, the Pences huddled together inside a Capitol office guarded by Mike Pence’s Secret Service detail and later took an unknown evacuation route to a secure room in the Capitol complex.

Greg Pence on Thursday repeatedly declined to say whether he would be willing to testify if a commission is created.

“You’re speculating,” he told a reporter. “And we’ll address that at that time. . . . We’ll see what happens here. Okay? Seriously. I don’t think it’ll get through the Senate.”

After condemning President Donald Trump’s actions around the Jan. 6 Capitol riot, multiple GOP lawmakers have since thrown their support behind him. (JM Rieger/The Washington Post)

Still others, such as House Minority Leader Kevin McCarthy (R-Calif.), who has told others he wants to stay on good terms with Trump and takes pride in how he manages their relationship, gave conflicting answers on the issue.

“Sure,” McCarthy said when asked at his weekly news conference whether he would testify about his contact with Trump on the day of the attack.

But in a later exchange with reporters, McCarthy declined to say whether he thinks lawmakers issued a subpoena to testify before the commission should comply.

“That’s a hypothetical. Talk to me if it goes through,” McCarthy said. He then remained silent when asked whether anyone who spoke with Trump on Jan. 6 should testify.

The accounts of Republican lawmakers’ interactions with Trump or his aides on Jan. 6 is based on their public comments, the recollections of people they spoke to about the conversations or people familiar with what happened who spoke on the condition of anonymity to describe the sensitive political situation.

McCarthy has been a vocal critic of the proposed commission, calling it politically motivated and unnecessary — after giving Rep. John Katko (R-N.Y.) his proxy to negotiate a bipartisan deal. The violent attack resulted in five deaths and left 140 police officers injured.

The House on Wednesday passed legislation that would establish the independent commission. Thirty-five Republicans joined Democrats in supporting the measure. But its chances in the Senate dimmed after McConnell announced his opposition, calling it a “slanted and unbalanced proposal.”

If he testifies, McCarthy is likely to be asked about his Jan. 6 phone call with Trump — a conversation he has described to others as distressing. A shaken McCarthy reportedly asked the then-president to help calm his supporters who had broken into the Capitol that afternoon, with some of them threatening to hang Pence and physically harm House Speaker Nancy Pelosi (D-Calif.).

Trump seemed uninterested, according to a statement from Rep. Jaime Herrera Beutler (R-Wash.), who talked to McCarthy about the call.

“When McCarthy finally reached the president on January 6 and asked him to publicly and forcefully call off the riot, the president initially repeated the falsehood that it was antifa that had breached the Capitol,” Herrera Beutler said in a statement earlier this year, referring a to loosely knit group of far-left activists. “McCarthy refuted that and told the president that these were Trump supporters. That’s when, according to McCarthy, the president said: ‘Well, Kevin, I guess these people are more upset about the election than you are.’ ”

McCarthy also spoke with senior White House adviser Jared Kushner, Trump’s son-in-law, after his conversation with Trump did not go well.

He, like McConnell, also spoke repeatedly with Pence and could testify that Trump was not part of the conversations to secure the Capitol.

One former senior Trump administration official directly involved in the day’s events said more than a dozen lawmakers tried to reach the White House to have Trump issue a public statement condemning the rioters.

Rep. Liz Cheney (Wyo.), who recently was ousted from leadership by House Republicans after frequently criticizing Trump’s repeated falsehoods about the election, has said in recent days that McCarthy should have to provide more information about his personal experiences and more on Jan. 6.

“He absolutely should, and I wouldn’t be surprised if he were subpoenaed,” Cheney said Sunday on ABC News’s “This Week.”

Cheney has also told others that she believes McCarthy has a conflict of interest because he was part of that day’s events and is worried about potentially having to testify.

Former congressman Zach Wamp, a Republican from Tennessee, is among those urging McCarthy to cooperate with any potential investigation. During a virtual news conference with reporters on Wednesday, Wamp said he believes McCarthy doesn’t have “anything to hide” from his conversations with Trump and that the GOP leader should testify “to kind of clear the air over what did happen.”

“Put our country above any political interest,” Wamp said. “Get it done in a manner that we can go into the 2022 election cycle with this behind us, not right in front of us. It’s in our best interest.”

Gorelick, meanwhile, noted that public pressure is likely to play a key role. She said that in the case of the 9/11 Commission, “the victims’ families were just brutal in their assessment” of lawmakers’ unsuccessful initial efforts to investigate the attack through a joint committee.

“When people ask me what made the 9/11 Commission a success, my first answer is an engaged citizenry,” she said.

A number of lawmakers outside congressional leadership could also have potentially valuable testimony if the commission becomes reality.

In the 48 hours before the siege, Trump spoke with conservative lawmakers, such as Rep. Mo Brooks (R-Ala.), to personally make sure they would be speaking at his rally on the Ellipse.

As the riot was unfolding, Trump accidentally called Sen. Mike Lee (R-Utah) while trying to reach Sen. Tommy Tuberville (R-Ala.). Lee passed his phone to Tuberville, who spoke with Trump for several minutes before the senators were evacuated from the chamber.

“I said, ‘Mr. President, they just took the vice president out, I’ve got to go,’ ” Tuberville told reporters in February.

Rep. Jim Jordan (R-Ohio) also rejected the idea that he or others should be subpoenaed to testify about their interactions with the former president.

“I think this commission is ridiculous, and why would they subpoena me? I didn’t do anything wrong — I talked to the president,” Jordan said. “I talk to the president all the time. I just think that’s — you know where I’m at on this commission — this is all about going after President Trump. That seems obvious.”

It’s unclear if Jordan meant he spoke with Trump on Jan. 6 and his office did not respond to a request to clarify his remarks.

Some Republican senators did not call Trump directly but went through other channels. In an interview in January, Sen. Lindsey O. Graham (R-S.C.) said he spoke with senior White House adviser Ivanka Trump, the president’s daughter, who said she was doing everything she could. He also spoke with Trump within 48 hours of the attack as well as the night of Jan. 5.

Mark Meadows, the president’s former chief of staff, was also fielding calls from lawmakers urging Trump to do something, according to people familiar with the activities that day.

One former administration official said at least a dozen Republican members of Congress called to pass along messages to Trump. Some left desperate voice mails.

“Kevin was the most aggressive in trying to get him to call them off,” the former official said.

Paul Kane and Eugene Scott contributed to this report.