WILLIAM BRANGHAM: After the presidential election, there was a spike in incidents involving neo-Nazi marches and racist and hateful messages sent online, stoking fear for people in a number of states across the country.

Stephanie Sy has more on this.

It's part of our Race Matters coverage.

STEPHANIE SY: William, in Waterloo, Iowa earlier this month, some residents received fliers advertising the Aryan Freedom Network.

That same week in Michigan, men waved Nazi flags outside a community theater production of "The Diary of Anne Frank."

Days later, in Columbus, Ohio, a small group of neo-Nazi men carried swastika flags.

And since the election, Black, Latino and LGBTQ Americans in at least 25 states, including kids and teens, have been subjected to racist text messages.

The messages told recipients to report to a plantation to pick cotton.

Des'tini LaGrone, a New Yorker, was one of the recipients of those texts.

DES'TINI LAGRONE, New York Resident: I truly felt fearful because this was the day after the election.

I didn't know if the winner of the election gave the authority for people to push hate, but then also fear for my safety in the sense of, who was able to obtain my information and violate my personal space as in contacting me to send such a thing?

Who has that type of hate in their heart?

STEPHANIE SY: For more on these incidents and what can be done, I'm joined by Margaret Huang, president and CEO of the Southern Poverty Law Center, an organization that monitors hate and extremism in the U.S. Margaret, thank you so much for joining the "News Hour."

As you know, the FBI is investigating those texts, but, as of now, we have no clearer sense of who sent them.

Based on the content, Margaret, what do you make of these mass texts?

And what is the intention behind them?

MARGARET HUANG, President, Southern Poverty Law Center: It's really clear to us that hate and extremist groups are using the election of Donald Trump as an encouragement to cause fear and anxiety in communities of color and religious communities and in the LGBTQ community.

Because of his use of racist, sexist, and other discriminatory rhetoric on the campaign trail, he's essentially encouraged his followers to spew hateful rhetoric, and he's emboldened them to embrace this hateful ideology.

STEPHANIE SY: You know, even if Trump has stirred up feelings of racial animus, he also saw gains, as you know, in this election among Latinos and African Americans.

With the second Trump term, do you expect that there will be more or less tolerance for this kind of hate speech?

MARGARET HUANG: I think that many people who supported the president-elect did so because they share his rhetoric and ideology.

But many other people did not.

Many people voted for him for economic reasons because they're frustrated by the economic situation of the country, and they wanted a change from what they were experiencing over the last few years.

That is not a mandate to embrace racial hatred or misogyny.

And I believe, in fact, that, as we move forward with the incoming administration, more and more people are going to reject that rhetoric and call for a change.

STEPHANIE SY: These mass text messages that were sent out, that seems unprecedented.

And we were hearing of middle schoolers who received these texts.

What can be done about that?

MARGARET HUANG: So, we actually spoke with students from across the country, including students from the University of Alabama, Troy University, University of West Georgia and Alabama State.

We also spoke with a 13-year-old in DeKalb County, Georgia, and a 14-year-old in Rockdale County.

It is very clear to us that the texts have been collected and sold by -- first from an international company to a domestic company, and then we have been unable to trace those texts, who purchased the text from that U.S. company subsequently.

We think that Internet companies that do this mass-text service need better regulations to ensure that they can report who is using those numbers they purchased for these kinds of activities.

And the FBI is currently investigating this trail of who purchased the texts.

STEPHANIE SY: Separately, white supremacist incidents, like the ones we just described have been rising for the last 18 months.

What would you attribute that to?

MARGARET HUANG: I think, again, so much of that was heard on the campaign trail from the candidate, candidate Trump himself.

I think that's what spurs so many other people to feel emboldened to embrace that rhetoric.

And I think we're going to see more of it for a time, particularly as Trump nominates people for senior-level positions in his administration who also echo that hateful rhetoric.

We're going to see more and more people openly embracing it.

But I will also note those incidents that you mentioned, Stephanie, where there were people marching or flyering, so far, those people have not sought to be identified.

They don't have the courage to identify with that rhetoric.

They just want to cause the fear that such activities usually spur.

And so it's important for people to stand proud in their communities and to reject this hateful rhetoric.

STEPHANIE SY: In this country, hate speech, including the display of swastikas, Nazi symbols, are all protected by the First Amendment.

What laws do come into play based on the incidents we have described?

MARGARET HUANG: There has been violence.

And, of course, on the campaign trail, there were also incidences of violence.

I think that is, in fact, the intention of these organizations.

They hope that this rhetoric and these hateful acts will actually encourage individuals to take action.

And that is why it is so important for us to focus on prevention and to speak out against hateful rhetoric whenever we can.

We need leaders in communities across the country, whether they are political, whether they are religious, whether they are community leaders, to speak out against hateful rhetoric and to reject any kind of that intolerance in their communities.

STEPHANIE SY: Margaret Huang with the Southern Poverty Law Center in Montgomery, Alabama, thank you.

MARGARET HUANG: Thank you.