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

House manager Rep. Joe Neguse, D-Colo., refuted arguments proposed by Trump's legal defense that Trump's speech was free political speech protected by the First Amendment. Neguse argued that Trump's free speech defense does not align with the facts of the events.

"To hear his lawyers tell it, he was just some guy at a rally expressing unpopular opinions," Neguse said. "They would have you believe that this whole impeachment is because he said things that one may disagree with."

Neguse also argued that free speech does not protect against insurrection, and that not holding Trump accountable would be a dangerous precedent for Congress to set.

"No president, no matter their politics or the politics of their followers, conservative, liberal, or anything else, no president can do what President Trump did. Because this isn't about politics. It's about his refusal to accept the outcome of the election and his decision to incite an insurrection. And there's no serious argument that the First Amendment protects that," Neguse said. "And it would be extraordinarily dangerous for the United States Senate to conclude otherwise."

Following a break, Rep. Joaquin Castro, D-Texas, returned to the Senate floor to address the harm he said was inflicted upon American national security on Jan. 6 and the longstanding damage to the country's international standing.

"Every foreign adversary considering attacking this building got to watch a dress rehearsal, and they saw that this Capitol could be overtaken," Castro said.

He then played a video of Republican Sen. Marco Rubio on Fox News saying the riot exposed a huge vulnerability on buildings across the U.S. government. Rubio said in the clip, "You are sitting out there watching this, you are saying it's not that hard to get into the Capitol and maybe it's not hard to get into the White House or somewhere else."

Castro also played video of rioters ransacking the desks that senators are currently sitting at in the chamber -- taking confidential information and screaming inside the Senate chamber, "Let's vote on s---!"

He said Trump has handed the Chinese government "an opening to create a false equivalency between Hong Kongers protesting for democracy and violent insurrectionists trying to overthrow it."

"To convict Donald Trump would mean that America stands the rule of law no matter who violates it. Let us show the world that Jan. 6, was not America. And let us remind the world that we are truly their North Star," Castro said.

ABC News Congressional Correspondent Rachel Scott discussed how inside the chamber, nearly 15 seats of GOP senators were empty as Democratic House managers made their case against Trump.

"You have some Republicans who appear to already have their minds made up," Scott said.

In order to convict the former president, every Democratic senator and 17 Republicans would have to vote in favor. ABC News' Chief Legal Analyst Dan Abrams said that to change the minds of some Republican senators, it might require a witness who offers something "game-changing."

"Unless they've got a witness who can really offer something that is game-changing, something where someone says 'Donald Trump did or didn't do this on or around January 6th,' I don't think it's a real chance that that's going to happen," Abrams said.

The shattered glass panes on the doors to the U.S. Capitol Rotunda from the East Front -- known as the Columbus Doors -- were replaced with new glass Thursday after sustaining damage during the Jan. 6 riot, according to the Architect of the Capitol's office. 

"Moving forward, we are looking at options to display a collection of items from Jan. 6," spokesperson Laura Condeluci told ABC News. 

The shattered glass was in place during Biden's inauguration, and he could be seen walking past the panes. 

Lawmakers have discussed various ways to display the glass and other vestiges of the attack around the Capitol. 

"It would be a good thing to preserve some evidence of the destruction of the building. So that 150 years from now, as people tour the building, they'll say, 'Ah, this was where that insurrection occurred,'" Sen. Mitt Romney told ABC News recently.

-ABC News' Benjamin Siegel and Trish Turner