Trump impeachment trial live updates: Biden says charge 'not in dispute' in 1st comments on acquittal

Lead House manager, Rep. Jamie Raskin, D-Md., said that the violent riot on Jan. 6 was a "culmination" of incitement to violence from Trump. He played a series of video clips from over several years, which Raskin said showed Trump urging violence.

"This pro-Trump insurrection did not spring into life out of thin air. We saw how Trump spent months cultivating America's most dangerous extremist groups," Raskin said. "We saw how he riled them up with corrosive lies and violent rhetoric, so much so that they were ready and eager for their most dangerous mission, invalidating the will of the people to keep Donald Trump in office."

Raskin cited the increase in hate groups and heightened threat from domestic terror, saying that Trump incited the anger of these groups for "his own political gain." The House managers also played footage from the Charlottesville, Virginia, "Unite the Right" rally which led to the death of one woman.

"These tactics were road tested. January 6th was a culmination of the president's actions, not an aberration from them," Raskin said. "The insurrection was the most violent and dangerous episode so far in Donald Trump's continuing pattern and practice of inciting violence -- but I emphasize 'so far.'"

House impeachment manager Rep. Diana DeGette continued to lay out the case against Trump on Thursday and argued how the insurrectionists themselves believed that they were following the president's marching orders.

"They truly believed that the whole intrusion was at the president's orders -- and we know that because they said so," DeGette said. "Many of them actually posed for pictures, bragging about it on social media, and they tagged Mr. Trump in tweets. Folks, this was not a hidden crime. The president told them to be there, and so they actually believed they would face no punishment."

Her main message is that rioters were there, solely, "because the president told them to be."

"The crowd at Donald Trump's speech echoed and chanted his words, and when people in the crowd followed his direction and marched to the Capitol, they chanted the same words as they breached this building," she said. "More and more insurrectionists are admitting that they came at Trump's direction."

DeGette went on to show news reports and video clips of rioters during and following the Jan. 6 attack saying they believed they were acting lawfully and as Trump had requested.

She said rioters would not have been in Washington had they not been invited by the president to falsely "stop the steal" -- and they would not have stormed the Capitol if Trump didn't embolden them to do so.

Senate Democrats are focused on trying to tie a direct line between Trump's rhetoric and the deadly attack on the U.S. Capitol by his supporters.

An ABC News investigation into the nearly 200 accused rioters facing federal charges for their alleged involvement at the Capitol -- based on court filings, military records, interviews, and available news reports-- found that at least 15 individuals who stormed the building have since said that they acted based on Trump's encouragement, including some of those accused of the most violent and serious crimes.

Trump's lawyers have defended his comments at the Jan. 6 rally as ones that "fall squarely within the protections of the First Amendment."

-ABC News' Olivia Rubin, Alexander Mallin and Alex Hosenball

Congresswoman Stacey Plaskett's life journey has taken her from the housing projects in Brooklyn, New York, to a historic role as House impeachment manager in the second Senate trial against Trump.

A delegate from the U.S. Virgin Islands, Plaskett is one of nine Democrats tasked with prosecuting the House's impeachment case against Trump.

On Wednesday, Plaskett presented new evidence in the impeachment trial -- showing previously unreleased videos of the riot at the Capitol on Jan. 6, contending Trump "fanned the flame of violence, and it worked."

She is also a former law student of lead impeachment manager Rep. Jamie Raskin, D-Md., who was a constitutional law professor at American University. As he introduced her Wednesday afternoon as the first delegate to participate in a Senate trial, Raskin reflected that introducing Plaskett during the Senate trial is "a moment of special pride for me."

"I hope I'm not violating any records or laws saying she was an A student then and an A+ student now," Raskin quipped.

Plaskett, who grew up in Brooklyn and a housing community on Saint Croix in the U.S. Virgin Islands, also said Wednesday she was a congressional staffer during the terrorist attacks on Sept. 11, 2001. Now a mother of five, Plaskett sheltered in her office during the siege on the Capitol.

-ABC News' John Parkinson