As the House committee investigating the Jan. 6, 2021, attack on the Capitol has built its public case that Donald J. Trump was at the center of an attempted coup, the panel has relied heavily on a seemingly unlikely stream of witnesses: Mr. Trump’s own advisers, his fellow Republicans and even his own family.
Those closest to Mr. Trump have been deposed, portrayed or shown dismissing the former president’s false claims that the 2020 election was stolen. And yet the fight to thwart the will of the people continued unabated.
The powerful testimony from a parade of Republicans, in four tightly produced hearings, has exposed in searing and consequential detail how divided the party has become between the faction that accepts the reality of the 2020 election and the many more who still cling to Mr. Trump’s anti-democratic falsehoods about a stolen election.
“If any Republicans were watching it, there is really no way they could defend a position that President Trump won the election based on the evidence presented so far,” said Mick Mulvaney, a former acting White House chief of staff to Mr. Trump.
There have been brief video clips of the former president’s daughter, Ivanka Trump, and unsparing testimony from a top White House attorney, Eric Herschmann, who said he scolded another pro-Trump attorney as “out of your” mind for continuing to pursue conspiracies to stop President Biden’s inauguration even the day after the Capitol riot.
“We’ve got lots of theories,” Rudolph W. Giuliani, one of Mr. Trump’s lead lawyers, told a group of state legislators as he sought to forestall the results, according to testimony on Tuesday from Rusty Bowers, the Republican speaker of the Arizona House of Representatives. “We just don’t have the evidence.”
The president’s former attorney general, William P. Barr, had one word for the swirling fact-less theories of fraud embraced by Mr. Trump in the election’s aftermath: “Bullshit.”
“I told him that it was, it was crazy stuff,” Mr. Barr said in his video deposition of claims of voting machine fraud, “and they were wasting their time on that, and it was doing grave, grave disservice to the country.”
But Mr. Mulvaney said that the partisan nature of the Democratic-led proceedings — the Republican leadership boycotted the panel after House Speaker Nancy Pelosi nixed some of their appointees — meant that fewer Republicans were likely to tune in.
Democrats fully control the investigative committee, though its members include two anti-Trump Republicans, one of them Representative Liz Cheney of Wyoming, the vice chair.
“The fact that there are Republican witnesses is very compelling,” Mr. Mulvaney said. “I don’t think Bill Barr is lying. I also know I am not seeing his entire testimony. I am going to see the pieces of his testimony that the Democrats want me to see.”
On Tuesday, Mr. Bowers and two Republican officials from Georgia testified under oath, describing in harrowing terms the pressure campaign they endured for standing up to the president and the toll that it took on them personally. On Thursday, more testimony is coming from inside the top ranks of Mr. Trump’s Justice Department.
“The committee has been brilliant in that tactic of using senior officials, family members, those high up in the campaign and Republicans who supported him,” said Stephanie Grisham, the former White House press secretary, who served under Mr. Trump for almost his entire term but has since emerged as a critic. “That’s what gives me hope that it will break through.”
A new Quinnipiac University poll on Wednesday suggested that such a breakthrough with large numbers of Republicans may still be a ways off.
While nearly six in 10 Americans overall think Mr. Trump bears a lot or some responsibility for the events of Jan. 6, the poll found, the opposite was true just among Republicans: 25 percent said he bears “not much” responsibility, and 44 percent said he bears none at all.
“My level of hope that there is room for a sane wing of the Republican Party to become ascendant again — the chances of that are extremely low,” said Sarah Longwell, a founder of the anti-Trump Republican Accountability Project.
Still, in two focus groups of 2020 Trump voters that Ms. Longwell has held since the hearings began, she said she noticed an unusual shift: Not one of the attendees wanted Mr. Trump to run in 2024.
“What was interesting to me: They liked Trump, but they want to move on,” Ms. Longwell said. “Which is exactly how they talked about Jan. 6 in general.”
Ms. Cheney, Mr. Trump’s most prominent Republican critic in Congress, has been direct about her goal to try to drive a wedge between Mr. Trump and the party’s base, if not between him and the party’s elected leaders in Washington.
“I say this to my Republican colleagues who are defending the indefensible: There will come a day when Donald Trump is gone, but your dishonor will remain,” Ms. Cheney said at the first hearing, on June 9.
Ms. Cheney, who is facing a Trump-backed primary challenger this summer, has positioned herself as a potential presidential candidate against Mr. Trump should he run. Next week, she is slated to deliver a speech on the future of the party at the Reagan Library in California, the same venue where a number of ambitious, potential Republican contenders in 2024 have appeared in recent months.
Several Republican strategists predicted that the Jan. 6 committee hearings would have less of an impact on the 2022 midterms — when Mr. Trump himself is not on the ballot — than on the 2024 Republican presidential field.
On Capitol Hill, few were as blunt about the threat posed by Mr. Trump as J. Michael Luttig, a former federal appeals court judge, who is hardly a household name but holds great stature in the conservative legal world.
“Donald Trump and his allies and supporters are a clear and present danger to American democracy,” Mr. Luttig said in testimony last week.
Mr. Luttig then made the same forward-looking leap to the next presidential election that many Democrats are hoping voters will make as they vote in this fall’s midterms: If elected, Trump allies “would attempt to overturn that 2024 election in the same way that they attempted to overturn the 2020 election,” he warned.
At times, the committee’s indictment has been so focused on Mr. Trump, and so full of praise for the few Republicans who stood up to him, that some Democrats privately fear the strategy could backfire — by setting Mr. Trump apart from a Republican Party that, in fact, remains deeply loyal to him.
“It’s absolutely infuriating,” said Jessica Post, the executive director of the Democratic Legislative Campaign Committee, which is involved in statehouse races. “There is a much broader story than is being told by the Jan. 6 committee about the anti-democracy forces in the states.”
She was particularly frustrated at the lionization of Mr. Bowers merely for upholding the law, noting that Arizona had passed more restrictive voting bills on his watch. “I just don’t think you get a gold star for doing the absolutely least,” Ms. Post said.
Sitting next to Mr. Bowers on Tuesday was Georgia’s Republican secretary of state, Brad Raffensperger, who earned plaudits from the committee as a “public servant.” That same day, Georgia Democrats nominated a state representative, Bee Nguyen, to run against him, and on Wednesday Ms. Nguyen assailed Mr. Raffensperger’s past support for greater restrictions on voting.
The divide in the G.O.P. can easily be overstated: Some of those whose words have been used as a cudgel against Mr. Trump still say they would vote for him in 2024, should he be the nominee, including Mr. Barr and Mr. Bowers, who told The Associated Press this week, “If he was up against Biden, I’d vote for him again.”
Another Republican whose courage has been hailed by the committee is the former vice president, Mike Pence, for resisting Mr. Trump’s intense pressure to overturn the election.
Greg Jacob, Mr. Pence’s counsel, testified that one of Mr. Trump’s advisers, John Eastman, had asked Mr. Pence not to certify the Electoral College results even in the immediate aftermath of the Capitol riot.
“That’s rubber room stuff,” Mr. Pence told him, as Mr. Jacob recalled. In other words, Mr. Jacob said, “certifiably crazy.”
The committee’s hearing on Thursday will be about Mr. Trump’s “attempt to corrupt the country’s top law enforcement body, the Justice Department, to support his attempt to overturn the election,” as Representative Bennie Thompson of Mississippi, the Democratic committee chairman, previewed it.
Three senior Trump administration alumni are lined up as the star witnesses: Jeffrey A. Rosen, the former acting attorney general; Richard Donoghue, the former acting deputy attorney general; and Steven Engel, the former assistant attorney general for the Office of Legal Counsel.
The lawmaker leading the questioning will be another Republican: Representative Adam Kinzinger of Illinois.