GEOFF BENNETT: And, as our coverage continues, we're going to focus now on how Mr. Trump's calls for protests regarding his arrest have sparked concerns about the possibility of fresh political violence.

Laura Barron-Lopez joins us now to talk about how security officials are monitoring and preparing for a host of possible threats.

Thanks for being here.

And, Laura, I know you have spent the day tracking reaction to today's developments among Mr. Trump supporters, his Republican allies.

What have you found?

LAURA BARRON-LOPEZ: So, first off, a number of those who support the president, House Speaker McCarthy called this weaponization of government.

Senator Ted Cruz called it a frivolous -- frivolous charges.

Marjorie Taylor Greene, the Georgia Republican, said that she and other Republicans will never abandon the president.

So there still is a lot of rallying around the former President Trump.

But I want to also highlight some of the recent polling that dropped after the indictment.

So a CNN poll that got reaction to the indictment showed that 60 percent of Americans approve of the indictment, 40 percent disapprove.

But when it comes to Republicans' opinion of Trump, 72 percent of Republicans still have high favorables of Trump; 23 percent have unfavorable views of him.

So he very much still has a grasp on that base.

And another data point here is that the Trump campaign said that they have fund-raise some $10 million since the news of his indictment.

GEOFF BENNETT: Well, as we reported, Donald Trump supporters and anti-Trump protesters, they swarmed the streets outside the courthouse today.

That was a spectacle.

Beyond that, there are real concerns about the net effect of Donald Trump using this arrest and arraignment to rile up his supporters.

You have been speaking to extremist experts about that.

What do they have to say?

LAURA BARRON-LOPEZ: So, the experts that I have been speaking to say that it's not necessarily that they're looking at violence to break out at a protest like the one that was held today, but that they're looking at right-wing extremism groups, white militias, neo-Nazis, essentially, the coordinated white power movement that has grown since 1983 and has really mobilized in the Trump era.

I spoke to Kathleen Belew.

She's a historian at Northwestern University, an expert in the white power movement.

And she offered this warning: KATHLEEN BELEW, Northwestern University: What we have here with the indictment is an opportunity for extremists who are interested not in any kind of Americanism, but instead are interested in overthrowing the United States to create a white ethno-state.

This gives those folks an opportunity to reach into the Trump base, to find people who are frustrated and disaffected by this ruling, and to recruit and radicalize for their own purposes.

LAURA BARRON-LOPEZ: So, you heard Belew say there that, essentially, the indictment, the arrest, the subsequent revelation of the charges all can act as a triggering action for extremist groups.

GEOFF BENNETT: But, Laura, there are people who argue that Donald Trump's influence is waning, despite his sizable command over a certain part of the Republican base.

He doesn't draw the same big crowds.

He doesn't use Twitter in the way that he used to.

Does that lessen the prospects for political violence, based on your reporting?

LAURA BARRON-LOPEZ: So I asked Kathleen Belew exactly about this and whether or not his influence was waning.

And she essentially said that Trump is still seen as a figurehead for the militant right and for white power groups, but it goes beyond him.

KATHLEEN BELEW: This is a movement that organizes in cells and that uses any open window for what it attempts to do.

Even if his crowd attendance is waning, even if the mainstream part of his movement is waning, the continued callouts to extremists are still there.

And we're not talking about a group of people that needs a large number in order to effectively mobilize violence.

LAURA BARRON-LOPEZ: And so when Belew talks about the potential for militant groups to take action or a so-called lone wolf, essentially, they look -- or they're looking at right now the upcoming Oklahoma City bombing anniversary on April 19.

They said that what people should be on the watch for is potential attacks on federal buildings, on power stations and other paramilitary -- paramilitary activity.

GEOFF BENNETT: What does the online chatter suggest?

We know that extremists were very active on social media in advance of the January 6 attack.

What do the experts that you have been talking to say about that?

LAURA BARRON-LOPEZ: So I spoke to Colin Clarke, who's a senior researcher at the Soufan Center, which tracks extremism, and he's looking at Web sites like Telegram, Gab and other alt-right sties.

And, essentially, what he told me was that in the last 24 to 48 hours, there's been more volume, more vitriol about Trump's arrest and language like "Take our country back."

And he also said that, especially on Telegram, what it's reminding him of is the frenzy, the social media storm that occurred after the FBI raided Mar-a-Lago, when we saw that Cincinnati -- in Cincinnati, a gunman attack the FBI office there.

GEOFF BENNETT: Laura Barron-Lopez, thank you so much for that reporting.

LAURA BARRON-LOPEZ: Thank you.