GEOFF BENNETT: Former President Donald Trump is under fire again for comments made during a controversial speech at a campaign event for a Republican Ohio Senate candidate.

Extremism experts say it's the latest example of Donald Trump using violent rhetoric to appeal to his supporters.

At a campaign rally in Ohio Saturday, a tribute to those charged and convicted of crimes connected to the January 6 attack on the U.S. Capitol.

MAN: Please rise for the horribly and unfairly treated January 6 hostages.

GEOFF BENNETT: And a vow from the former president to release them.

DONALD TRUMP, Former President of the United States (R) and Current U.S. Presidential Candidate: We're going to work with the people to treat those unbelievable patriots... GEOFF BENNETT: As his use of the word bloodbath during an extended riff on the auto industry in Chinese automakers sparked fresh controversy and criticism.

DONALD TRUMP: No, we're going to put a 100 percent tariff on every single car that comes across the line.

(CHEERING AND APPLAUSE) DONALD TRUMP: And you're not going to be able to sell those cars, if I get elected.

Now, if I don't get elected, it's going to be a bloodbath for the whole -- that's going to be the least of it.

It's going to be a bloodbath for the country.

That will be the least of it.

GEOFF BENNETT: In a social media post today, Mr. Trump said his threat had been taken out of context and turned the defense of his comments into a fund-raising appeal.

Former President Trump also facing criticism for his dehumanizing anti-immigrant rhetoric at that same rally.

DONALD TRUMP: If I had prisons that were teeming with MS-13 and all sorts of people that they have got to take care of for the next 50 years, right, young people, they're in jail for years and - - if you call them people.

I don't know if you call them people.

In some cases, they're not people, in my opinion.

GEOFF BENNETT: And in a FOX News interview Sunday, he doubled down on past comments about migrants that echo dictators.

HOWARD KURTZ, FOX News Anchor: Why do you words like vermin and poisoning of the blood?

The press, as you know, immediately reacts to that by saying, well, that's the kind of language that Hitler and Mussolini used.

DONALD TRUMP: Well, that's what they say.

I didn't know that, but that's what they say.

Because our country is being poisoned.

GEOFF BENNETT: Experts who study extremism say the former president's bloodbath remark is part of an escalating campaign of violent rhetoric.

BRENDAN NYHAN, Dartmouth College: In this case, it may have been a metaphor.

It's hard to tell with him.

He was using that language in the context of a discussion of the auto industry, but his meaning was ambiguous.

Given the way he so frequently calls for or endorses violence, I think it's appropriate to be concerned when he invokes it even in a seemingly metaphorical way.

GEOFF BENNETT: Dartmouth College political science professor Brendan Nyhan has closely followed Mr. Trump's commentary about immigrants over the last decade.

He says Donald Trump's rhetoric should be viewed through an historical lens.

BRENDAN NYHAN: Donald Trump's descriptions of people from other countries and other racial and ethnic groups as subhuman animals is the kind of language we see in countries before they have ethnic violence or even genocide.

It's the kind of language we see when authoritarian movements rise to power.

He's appealing to the worst aspects of humanity.

It's straight out of the textbooks, and we should be very worried with how mundane it now seems.

GEOFF BENNETT: President Biden's campaign in a statement responding to Donald Trump's rally remarks said -- quote -- "He wants another January 6, but the American people are going to give him another electoral defeat this November, because they continue to reject his extremism, his affection for violence, and his thirst for revenge."