RACHEL MARTIN, HOST:

For more on this weekend's dramatic events, NPR's national political correspondent, Mara Liasson, joins us. Hi, Mara.

MARA LIASSON, BYLINE: Hi, Rachel.

MARTIN: It doesn't matter your politics, really, watching Americans take swings at one another at political rallies is disconcerting. Frankly, the political environment is scaring a lot of people right now. How did we get to this place?

LIASSON: Well, a lot of people are talking about that. Some Republicans I've talked to agree that the roots of this can be found in a lot of things - the tremendous anger at government that the Tea Party and even the Republican Party, they admit, have stoked, the talk show culture - say anything, demonize your enemy - the stagnating economy, the fear of terrorism. But overall, what Republicans tell me is that the match that lit this fire is Donald Trump. A lot of his supporters are angry, but he's channeled that anger, they say, in a racial direction against Mexicans, against immigrants. He's said from the podium at his rallies, I wish I could punch that protester in the face. He encouraged his supporters to, quote, "knock the crap out of a protester," and promised to pay their legal fees if they did. So there have always been angry voters and protesters, but Trump attracts more of them than anyone else. His supporters feel that the American way of life they knew is slipping away. Protesters feel Donald Trump represents hatred and bigotry. And as we saw over the weekend - they clashed, and it looked like it was spiraling out of control.

MARTIN: So all these protests - is any of this changing the race in any way?

LIASSON: Well, Republican rivals to Trump are blaming him. Ted Cruz said the culture of the - of a campaign is created by the candidate. John Kasich said Trump created a toxic environment. Marco Rubio has said he's acting like a third-world strongman. So they're talking about the demagoguery and the authoritarian, violent rhetoric. They're - tremendous anguish among his rivals. They all promised that they would support him if he was the nominee, but Marco Rubio and John Kasich have now said that despite their pledge, it's getting harder and harder for them to support him if he is the nominee. Now how this affects actual Republican voters is harder to measure. A lot of Trump supporters feel mad that they weren't allowed to hear their candidate. They feel their first American - First Amendment rights were violated in Chicago, so on some level it probably makes them even more ardent supporters of Trump.

MARTIN: Let's look ahead to Tuesday. A lot of big states voting - Florida, Illinois, Missouri, North Carolina and Ohio. Remind us of the stakes.

LIASSON: Stakes are very high. If Trump wins just Ohio and Florida, the two biggest winner-take-all states, he will be unstoppable. Kasich and Rubio, if they don't win their home states, will have a hard time justifying staying in the race. If they can win their home states, Trump could get to the Cleveland convention without the 1,237 delegates needed to be nominated on the first ballot. After the first ballot, as you heard earlier in the show, delegates are unbound. They're free to vote for whoever they want, and the campaigns are already working to make sure they have delegates ready to vote for them if that happens.

MARTIN: NPR national political correspondent Mara Liasson. Thanks so much, Mara.

LIASSON: Thank you. Transcript provided by NPR, Copyright NPR.