Tear gas swirls around a mob of Trump supporters at the Capitol on Jan. 6, 2021. Photo for The Washington Post by Evelyn Hockstein

WASHINGTON — Former President Donald Trump’s actions – and inaction – during the Jan. 6, 2021, attack on the Capitol will take center stage at Thursday’s prime-time hearing, as the committee investigating the assault wraps up more than a month of public airing of its findings.

A select committee aide who briefed reporters Wednesday said the hearing is being referred to internally as the “187 minutes hearing,” a reference to the time between the end of Trump’s rally at the Ellipse that day and his recorded remarks in the Rose Garden.

Members previously said it is part of an effort to tie Trump to the attack, as well as the campaign to overturn his loss in the 2020 election, as the committee tries to lay out what caused the assault and ways to prevent its reprise.

“President Trump had the power to call off the mob. He was the sole person who could have called off the mob and he chose not to,” aides said.

Testimony from people who were in the West Wing on Jan. 6 would make clear what the president was doing, select committee aides said. One told reporters there was no reason to necessarily think this would be the final hearing.

“We have filled in the blanks,” Illinois Republican Rep. Adam Kinzinger, one of the panel’s two Republican members, told CBS News over the weekend.

“The reality is – I will give you this preview – the president didn’t do very much but gleefully watch television during this time frame. We’re going to present a lot more than that,” Kinzinger said.

Kinzinger, along with Rep. Elaine Luria, D-Va., is set to lead Thursday’s hearing, California Democratic Rep. Pete Aguilar told reporters Tuesday. It is expected to be chaired remotely by Chairman Bennie Thompson, D-Miss., who announced Tuesday he had tested positive for COVID-19.

The committee’s ninth hearing caps a two-month effort to document Trump’s efforts to overturn his election loss, from pushing the Justice Department to declare the election corrupt, to pressuring Georgia officials to “find the votes” to declare victory in the state, to his goading speech to the crowd at the Ellipse before the attack on the Capitol.

“This is about nailing the hammer home and putting all of that story together,” Duke University law professor David Schanzer said.

Schanzer, who studies extremism and terrorism, said he saw Thursday’s hearing as the culmination of the committee’s effort to show Trump was behind the violence that day.

“The committee has been focused on trying to demonstrate that Trump was a willing participant in how everything played out that day. As opposed to somebody who just was personally angry, gave an angry speech, and then bad stuff happened,” Schanzer said.

He pointed to testimony from witnesses like Cassidy Hutchinson, a former top aide to then-White House Chief of Staff Mark Meadows. At a hearing last month, she said she was told Trump wanted armed supporters at the Ellipse rally and lashed out at his Secret Service detail when they refused to take him to the Capitol after the speech. The service said it would respond on the record to her accusations, but has yet to do so.

“What’s really interesting is how many people came for a political rally, were deeply aggrieved and had bought into the whole narrative of grievance,” Schanzer said. “And then, frankly, to their surprise, ended up participating in the violence that day, and I think you can put that squarely on Trump.”

However, that effort has not gone as smoothly as the committee hoped. Key people in Trump’s inner circle have refused to testify, including former adviser Steve Bannon, who is currently facing a trial on contempt of Congress charges for his refusal to cooperate with the investigation.

On top of that, the committee has not been able to get texts and other documents from the Secret Service that could help corroborate – or dispute – Hutchinson’s testimony.

Homeland Security Secretary Alejandro Mayorkas confirmed Tuesday that the Secret Service moved forward with previously scheduled data migration after Jan. 6, which appears to have resulted in the deletion of text messages

“I will say that the Secret Service remains committed to cooperating fully with the committee, and I think there’s something just underlying all of this that we have to keep in mind,” Mayorkas said at the Aspen Security Forum. “We need to know exactly what happened on January 6th, and the days leading up to it and the days following it.”

A select committee aide on Wednesday declined to detail the engagements with Secret Service regarding the efforts to collect additional information given the reported data migration. The committee received only one text message related to Jan. 6 from the agency.

Further, several key witnesses like former White House Counsel Pat Cipollone have significant limits on their testimony. Stephen Gillers, a law professor at New York University, said Cipollone and other White House lawyers would have to weigh what they can say against the privilege they guard with their clients.

That’s already come up in the small amount of Cipollone’s testimony the committee aired. In a clip played during a hearing last week, Cipollone asserted an unspecified privilege exemption when committee investigators asked why he was excluded from at least one White House meeting.

Gillers called the committee’s subpoena to Cipollone “window dressing” that would not compel much testimony from the attorney.

“The subpoena is just a way of getting him in the room. What he says in the room is something separate,” Gillers said.