House Democrats have sought out new cellphone footage of the Capitol siege as well as updated details about injured police officers as they seek to build an emotionally compelling impeachment case against former president Donald Trump.

The goal is to present the Senate with fresh evidence that reveals what Trump knew in advance of the Jan. 6 rampage at the Capitol, as well as how his words and actions influenced those who participated. The rioting left five dead, including one member of the U.S. Capitol Police. In addition, two officers, one with the D.C. Police Department, have since died by suicide.

The effort to present new video evidence and witness testimony appears designed to make Republican senators as uncomfortable as possible as they prepare to vote to acquit Trump, as most have indicated they will do. The prospect of injured police officers describing the brutality of pro-Trump rioters to Republicans who regularly present themselves as advocates of law enforcement could make for an extraordinary, nationally televised scene.

Democrats and Republicans on Jan. 17 recalled personal experiences of the Capitol riots and discussed then-President Donald Trump's looming impeachment trial. (The Washington Post)

Yet the strategy appears to be on a collision course with the Senate, where Democrats and Republicans alike have expressed reluctance to allow witness testimony in the interest of limiting the trial’s length to about a week. Both parties are eager to move past the final days of Trump’s presidency, with Democrats hoping to turn their attention to President Biden’s ambitious legislative agenda, and Republicans hoping to shift attention away from their standard-bearer’s role in the shocking riot.

The House impeachment managers are determined to present as much evidence as senators allow, to ensure a permanent record of Trump’s role in the riots — and to force Republicans to witness the chaos and carnage one more time before they vote against conviction, several individuals familiar with Democratic thinking said.

“Our goal is conviction,” said one person working on strategy with the House impeachment managers, referencing a House Republican from Wyoming who voted with Democrats to impeach Trump. “What story are we going to tell to get there? We are going to describe what happened as summarized by Liz Cheney when she announced her support for Trump’s impeachment: ‘He summoned the mob, assembled the mob, and lit the flame of this attack.’ ’’

The Democrats are taking control of the Senate as an impeachment trial, cabinet nominations and an ambitious Biden agenda are all on the table. (The Washington Post)

House Democrats are assuming they will be permitted to play a compilation of footage from Jan. 6, including newly released cellphone recordings of protesters attending Trump’s “Stop the Steal” rally that morning, said these individuals, who spoke on the condition of anonymity to discuss private conversations. The compilation will also likely feature footage from inside the Capitol after protesters breached it.

The footage is being collected by House managers and support staff, and compiled by the law firm Debevoise & Plimpton, which produced audiovisual materials for Trump’s first impeachment trial when he faced charges that he had solicited foreign interference to help his reelection bid.

Video, audio and other visual materials are considered even more pivotal to making the case for conviction in Trump’s second impeachment trial, according to aides involved in House Democrats’ strategy.

House Democrats chose a law firm to do the audiovisual work rather than an entertainment company, aides said, to avoid too much glitz and to ensure a properly somber final product similar to what might be used in a courtroom.

A spokeswoman from Debevoise & Plimpton declined to comment Friday when asked to confirm the firm’s involvement.

Most Republican senators have signaled they are prepared to acquit on the theory that it is unconstitutional to try a former president on impeachment charges — sparing them from having to evaluate Trump’s conduct. That theory is contested by many constitutional scholars, but it has gained a foothold in the GOP ranks.

“It will all be theater,” Sen. Rand Paul (R-Ky.) said of a trial Thursday.

House managers and their staff, meanwhile, have been busy at work — closely reviewing footage scraped from Parler and other sites revealing previously unseen moments in the hours before, during and after the Capitol assault. One such video was posted last week by the website Just Security. It showed demonstrators listening to Trump’s words and reacting emotionally and physically.

The goal, according to aides, is to weave together a presentation that both reminds senators of what they lived through and shows how Trump’s words and actions helped incite the insurrection.

House managers are also well aware of reports from a Capitol Police officers’ union this week that 140 were injured in the melee, some seriously. One officer was killed, two subsequently died by suicide and others suffered brain injuries and cracked ribs. One is expected to lose an eye. The managers have asked regularly for updates. Although they continue to contemplate calling police as witnesses, they are also aware that the experience could be painful for the officers.

It is unclear whether the impeachment managers will be permitted to call witnesses. People working with the House managers said they have discussed a wish list of potential witnesses. Sen. Ben Sasse (R-Neb.) told talk show host Hugh Hewitt that top aides told him that Trump was “walking around the White House confused about why other people on his team weren’t as excited as he was as you had rioters pushing against Capitol Police.”

It is unlikely they will call White House witnesses, one participant in impeachment discussions said.

But it will fall to the Senate to choose whether to compel testimony. The trial’s rules are still under negotiation and may not be finalized until shortly before the proceedings are set to begin on Feb. 9.

And the question of whether to allow witnesses may not be settled by then: In Trump’s first trial, Democrats brought a motion to call witnesses after nine days of opening arguments. The motion was defeated on a 51-to-49 vote that saw only two of 53 Republicans join Democrats, and Trump won acquittal five days later.

Senators and aides, many of whom spoke on the condition of anonymity to candidly describe internal discussions, said this week that there is an emerging desire this time around to keep the trial’s length roughly a week — less than half the length of Trump’s first trial.

That reflects a bipartisan intersection of interests: After a test vote Tuesday showed only five Republicans willing to break with Trump, most Democrats want to get past the trial and muscle through Biden’s $1.9 trillion pandemic relief package. GOP senators, meanwhile, are eager to put the incident in the rear view mirror.

“I would expect that it would be fast,” said Sen. Roy Blunt (R-Mo.), the No. 3 GOP leader.

Tuesday’s test vote, said Sen. Thom Tillis (R-N.C.), “gave an indication of how the impeachment trial’s likely to end up.”

“We need to heal the American people,” said Tillis, who voted with most Republicans to continue debating the trial’s constitutional basis. “I’m really more focused on moving ahead, and getting most people focused on healing the economy, recovering from covid, and getting back to the very, very optimistic view that most Americans had just a year ago in February.”

Unlike last year’s trial, managers are presenting only one article, not two, and some senators — such as Sen. Tim Kaine (D-Va.) — have suggested that a multiday question-and-answer period can be skipped this time, given lawmakers’ familiarity with the events.

Kaine and others have floated a proposal to censure Trump as an alternative that could attract more GOP support. But top Democratic leaders insist there will be a trial regardless — though they have not specified how long it might run.

Sen. Richard J. Durbin (D-Ill.), the majority whip, said the Senate had a “responsibility” to do so.

“I want — I hope — to see the House managers make a clear record of what happened on Jan. 6 that will be available for the current senators and any future senators and representatives who want to know the reality of that event,” he said. “The fact that it is being distorted in news already shows that there are people determined to rewrite history and point the finger and blame in another direction.”

Asked Thursday if Trump could receive a fair and complete trial in the span of a week, House Speaker Nancy Pelosi (D-Calif.) said, “Of course, of course.”

“I don’t know how long it will take. It depends on the response that [Trump] will make,” she said. “But it will be a fair trial and respectful of the role that the Senate plays.”

House Democrats are also investigating a gathering of Trump’s allies and family members at the Trump International Hotel in D.C. the evening before the insurrection at the Capitol.

The gathering took place in what’s known as the Trump Townhouse, a two-story space available for rent, and was described by one person familiar with the event, who spoke on the condition of anonymity, as a small gathering of donors and other Trump allies to watch the returns in Georgia’s two Senate runoffs.

Trump’s son Donald Trump Jr. was among those who stopped by the gathering, according to the individual; former Trump campaign manager Corey Lewandowski also confirmed that he was there, though he said he had no discussions about the following day’s planned rally. Trump Jr. declined to comment.

An aide working with the House impeachment managers said the gathering is of “medium” interest because the former president did not attend and their primary focus is on what he knew ahead of the riots and what he did to encourage the violence.

Clarification: An earlier version of this story reported that Sen. Tim Kaine (D-Va.) had proposed censuring Trump in lieu of an impeachment trial. While Kaine floated such a proposal in a Wednesday interview with The Post, in remarks to other reporters on Thursday he acknowledged that the trial would move forward, with a possible censure vote afterward if Trump is acquitted. The story has been updated.

David A. Fahrenthold, Paul Kane, Emma Brown and Peter Hermann contributed to this report.