Ahead of the trial resuming on Friday, Sen. John Thune of South Dakota -- the No. 2 in GOP leadership -- questioned the effectiveness of the defense team using videos of Democrats saying similar words that Trump has used. He said he isn't sure "that it bears a lot on this case."

However, it's a strategy the defense team is leaning into with its arguments.

"They may show some videos of other similar incidents, which I don't know if that's an effective strategy," Thune said.

Asked if there was an equivalency to what happened at the Capitol on Jan. 6 and Democrats' past rhetoric, Thune didn't express confidence that Trump's attorneys would make that case.

"Well, that's what I'm saying, I don't know, I think we will see. It depends, I suppose, on how they tie it all together," he said.

Looking past the trial, Thune said he might be supportive of a censure to the former president and said it depends on if that measure could be "effective."

"I know there were a couple of resolutions out there," Thune said, adding that at least a couple "could attract some support."

He said he didn't think resolutions to bar Trump from running again would "go anywhere."

-ABC News' Trish Turner

The former president's legal team argued that the increased "hatred" in politics has led to more incendiary political language and that the First Amendment protections must be applied evenly across all political language.

"Will the Senate then have to deal with constant articles of impeachment by a majority party accusing minority presidents or other elected officials of so-called 'inciteful' or false speeches?" Michael van der Veen said. "You can see where this would lead."

Van der Veen argued that Trump's speech and the speech of other politicians is protected by case law and the Constitution, and accused House managers of urging senators to ignore that.

"They astoundingly urge you to disregard your oath by ignoring the First Amendment of the Constitution. They also ignore landmark binding United States Supreme Court cases ... which unequivocally hold that elected officials have core First Amendment rights to engage in the exact type of political speech which Mr. Trump engaged in," van der Veen said.

Arguing Democrats are setting a "dangerous double standard," Trump attorney David Schoen played several mashup videos of notable Democratic figures calling for supporters to "fight" and clips of them questioning election results in years past, in an effort to paint Trump's rhetoric as normal political speech.

"Every single one of you and everyone of you, that's OK. You didn't do anything wrong. It's a word people use but please stop the hypocrisy," Schoen said.

Schoen argued that the Trump team was denied due process and that the reason for the impeachment is because of Democrats' strong dislike of Trump and the Republican Party.

"The House managers' position really is that when Republican candidates for office claim an election is stolen or the winner is illegitimate it constitutes inciting an insurrection and the candidate should know it. But Democratic Party candidates for public elected office are perfectly entitled to claim the election was stolen or that the winner is illegitimate or to make any other outrageous claim they can. It is their absolute right to do so," he said, pointing to claims around the 2016 election.

-ABC News' Allison Pecorin

When the chamber gaveled in, prayed and said the pledge on Friday, only 18 senators were in the chamber -- six of them Republicans. More flowed in as the proceedings began, but Senate Minority Leader Mitch McConnell was one of the last to arrive in the chamber at 12:12 p.m.

As Trump's lawyer Michael Van der Veen played footage showing Rep. Jamie Raskin, D-Md., objecting to the electoral college count in 2017, Raskin fiddled his thumbs. He seemed to notice the sound of his voice but didn’t look up at the screens immediately.

Republican senators appear much more alert compared to the past two days when the House impeachment managers presented their arguments. Many are taking notes and Sen. Rand Paul, R-Ky., has been particularly attentive today, seen chuckling several times, including when footage played showing Rep. Maxine Waters, D-Calif., challenging Electoral College results. He was also smiling and nodding as footage played of Democratic responses to protests over the summer.

On the other side of the chamber, some Democrats could be seen shaking their heads and whispering at times during the presentation. When Sen. Bernie Sanders, I-Vt., was mentioned in reference to the shooting of Rep. Steve Scalise, R-La., Sanders was seen fidgeting with the cuff of his shirt, leaned back in his chair and not taking notes.

After van der Veen finished his arguments, whispers broke out. Some Republican senators were nodding and giggling.

Reporters inside the Senate chamber noted that as David Schoen was talking, only three Republican seats were empty and almost all of senators were paying close attention. Sen. Bill Cassidy, R-La., continued to take notes, as he has throughout the trial.

When Schoen brought up what he alleged was manipulation of exhibits by House impeachment managers, lead House manager Raskin began scribbling in his notepad furiously. 

-ABC News' Trish Turner