Christopher C. Miller, the former senior Trump administration official who presided over the Pentagon’s Capitol-riot response, told lawmakers Wednesday that he believed “an organized conspiracy with assault elements in place” orchestrated the Jan. 6 insurrection.

The assessment — a departure from Miller’s previous public statements about what led to the assault on Congress — set off a political mudfight, as Democrats on the House Oversight and Reform Committee accused the former acting defense secretary of “incompetence,” and being “AWOL” and “disloyal to the country,” while Republicans accused their counterparts of harassing the hearing’s witnesses to further what they characterized as a partisan investigation.

Wednesday’s hearing marked the first time Miller has testified publicly before a congressional committee investigating the insurrection, which he described as “an act of terrorism.” His highly anticipated testimony was viewed as an opportunity for congressional investigators to fill in key gaps in their understanding of the security lapses that occurred Jan. 6, and to seek accountability for an hours-long delay before armed National Guard personnel responded to lawmakers’ frantic pleas for help. But instead, Miller offered defiance in the face of Democrats’ questions, refusing to share fault for the failures that transpired — and blaming officials on Capitol Hill for never sending the Pentagon a “valid request.”

“If you were the effing cavalry, you never showed up. You never got there on time, and we were exposed because of this,” Rep. Mike Quigley (D-Ill.) told Miller after nearly five hours of questioning Wednesday. “You lost, and you don’t have the intestinal fortitude to own up to your responsibility.”

The hearing turned combative early on, when Rep. Stephen F. Lynch (D-Mass.) pressed Miller about whether President Donald Trump’s Jan. 6 speech, during which he implored thousands of his supporters amassed near the White House to “fight like hell,” had incited the riot.

Miller, appearing remotely via a live video feed, said he did not believe Trump’s speech was the only reason for the day’s violence, citing the apparent degree of prior planning undertaken by some of the rioters.

On May 12, Former acting defense secretary Christopher C. Miller watered down his prior comments about former president Donald Trump’s role in the insurrection. (The Washington Post)

Lynch suggested Miller was contradicting the written testimony he provided the committee ahead of Wednesday’s hearing, in which he stated that he believed Trump’s comments had encouraged the protesters.

“Absolutely not, that’s ridiculous,” Miller said.

“You’re ridiculous,” the congressman shot back.

In the full written statement Miller submitted to the committee, he detailed multiple conversations with Trump in the days before the riot. Trump, Miller said, indicated that the Pentagon should give D.C. Mayor Muriel E. Bowser (D) any support she requested, and guessed that “they” would need 10,000 troops on Jan. 6 to contain the throngs of Trump’s supporters who came to the nation’s capital for a “Stop the Steal” rally. Miller omitted those passages — and his criticism of Trump’s speech to rallygoers — from the opening statement he delivered Wednesday, though later on, under questioning from lawmakers, he affirmed those points.

But when asked point-blank by the panel’s chairwoman, Rep. Carolyn B. Maloney (D-N.Y.), whether Trump upheld his constitutional oath, Miller was resolute in defending the former president. “Yes,” he replied.

As Democrats pounced, Miller became defensive. When Rep. Ro Khanna (D-Calif.) demanded he apologize to the country, Miller ignored the request, instead praising the work of the military personnel who responded to the riot. When Rep. Raja Krishnamoorthi (D-Ill.) said he was going to call for an official Pentagon investigation into his actions, Miller retorted that he had already requested such a probe before leaving his post at the end of January.

Miller’s sparring with the committee overshadowed the testimony of the hearing’s two other witnesses, D.C. Police Chief Robert J. Contee III and Jeffrey Rosen, Trump’s acting attorney general at the time of the attack.

But Rosen, also making his first public appearance before a congressional committee investigating the riot, did not escape scrutiny, as Democrats scoffed at his claims the Justice Department engaged in “very robust intelligence-sharing” with federal and local partners ahead of the violence.

“This appears to have been a Keystone cops operations when it comes to executive branch agencies pointing fingers at each other,” Rep. Debbie Wasserman Schultz (D-Fla.) said.

Rep. Jackie Speier (D-Calif.) accused law enforcement officials of trying to duck responsibility for failing to prevent the riot from happening, arguing that neither the FBI nor the Justice Department did enough to notify senior officials or other agencies of warnings indicating impending violence, or to call up reinforcements before the chaos erupted.

“It reminds me a lot of 9/11, where it never percolates to the top,” Speier said.

Rosen told lawmakers that, although no one had requested it, he directed various Justice Department agencies to take preliminary steps to prepare for the riot, including ordering an FBI SWAT team based in Baltimore to relocate to Washington for the day.

Throughout the hearing, Republicans scolded Democrats for “badgering” the former Trump administration officials and “partisan finger-pointing.” Several accused the panel’s Democrats of “hypocrisy” for investigating only the circumstances surrounding Jan. 6 and not last summer’s racial justice protests that erupted in several U.S. cities after the killing of George Floyd, some of which turned violent.

“You can’t ignore some acts of violence and use others for political gain,” Rep. James Comer (R-Ky.), the panel’s top Republican, said.

But some from the GOP’s ranks went after the witnesses, too. In one tense exchange, Rep. Paul A. Gosar (R-Ariz.) asked Rosen “who executed Ashli Babbitt,” a pro-Trump protester shot by Capitol Police when trying to enter the House chamber. Rosen said he was aware of Babbitt’s death but declined to discuss the case in any detail.

Maloney had tried to frame Wednesday’s hearing as a forum to learn why “security collapsed in the face of the mob, and reinforcements were delayed for hours as the Capitol was overrun.” She excoriated the Justice Department and Pentagon for failing, to date, to produce even “a single piece of paper” to any House committees investigating why law enforcement was overwhelmed by the approximately 10,000 pro-Trump rioters who gathered outside the Capitol, and the estimated 800 who stormed the building.

The inspectors general of multiple federal agencies, including those with purview of the Defense Department and the Justice Department, have undertaken an expansive investigation of the incident.

Miller testified that responsibility to call up the D.C. National Guard had been delegated to him by Trump well in advance of Jan. 6, but that he resisted Bowser’s early calls to deploy those troops for fear they would either be pilloried for trampling First Amendment rights or somehow “co-opted in an effort to overturn the election.”

Miller approved unarmed troops, per Bowser’s request, on Jan. 4, he said.

Miller said he never spoke to Trump on Jan. 6., though he did speak to Vice President Mike Pence as the Capitol attack unfolded. Miller said he approved the full deployment of the National Guard at 3 p.m. on Jan. 6, and that the order was transmitted to the head of the D.C. Guard four minutes later.

The first armed troops arrived at the Capitol at 5:22 p.m.

But Miller’s timeline differs from the Pentagon’s official rundown of events. He conceded, under questioning from Rep. Alexandria Ocasio-Cortez (D-N.Y.), that he did not give approval to the final mobilization plans until 4:32 p.m. — after speaking with Pence, and nearly three hours after Bowser first called him, requesting additional forces be sent to the Capitol to quell the swelling crowds.

Later, in response to a question from Rep. Hank Johnson (D-Ga.), Miller said he was unaware that Capitol Police Chief Steven A. Sund, who stepped down after the riot, was seeking National Guard backup as the riot unfolded.

Before the order was issued, several other federal government agencies — as well as the D.C. police department — had already mounted a response. According to Rosen, FBI SWAT and hostage-rescue teams; special-response teams from the Bureau of Alcohol, Tobacco and Firearms; and Federal Protective Service and Immigration and Customs Enforcement personnel from the Department of Homeland Security were on the scene by 2:40 p.m. — about a half-hour after rioters broke into the Capitol building.

During his brief tenure as acting attorney general, Rosen came under tremendous pressure from Trump and his allies to have the Justice Department investigate the outgoing president’s claims of voter fraud in the 2020 election. At one point, Trump even entertained a plan to replace Rosen — who stepped into the attorney general role on an acting basis when William P. Barr left the position on Christmas Eve — with Jeffrey Clark, an assistant attorney general who had demonstrated more sympathy to the president’s position.

In his written statement, Rosen was emphatic that during his time atop the Justice Department, “no special prosecutors were appointed, whether for election fraud or otherwise,” and that “no public statements were made questioning the election.” But when asked directly to say if he believed the election had been stolen from Trump, Rosen demurred. And when asked to detail his conversations with Trump about the 2020 election ahead of the riot, Rosen repeatedly refused.

Correction: A previous version of this article misidentified who asked former acting attorney general Jeffrey Rosen about the fatal shooting of a woman who breached the U.S. Capitol on Jan. 6. The question was asked by Rep. Paul A. Gosar (R-Ariz.), not Rep. James Comer (R-Ky.).