AMNA NAWAZ: Former President Donald Trump attacked his political opponents in a speech over the weekend that historians say echoed authoritarian leaders.

New York University historian Ruth Ben-Ghiat joins me now to discuss.

So, Ruth, this was a speech delivered in New Hampshire.

It was meant to mark Veterans Day.

For anyone who missed it, here is just part of what Mr. Trump had to say.

DONALD TRUMP, Former President of the United States (R) and Current U.S. Presidential Candidate: We will root out the communists, Marxists, fascists, and the radical left thugs that live like vermin within the confines of our country, that lie and steal and cheat on elections, and will do anything possible, they will do anything, whether legally or illegally, to destroy America and to destroy the American dream.

AMNA NAWAZ: Ruth, there is very specific language in there that caught a number of historians' attention, including yours, also the word vermin in particular.

What stood out to you from his remarks?

RUTH BEN-GHIAT, NYU History Professional: So, since the fascists, authoritarians always want to do two things -- they want to change the way that people see violence, making it into something necessary and patriotic and even morally righteous, and they want to change the way people see their targets.

And so they use dehumanizing language.

And former President Trump is doing both.

He's been using his rallies since 2015 to shift the idea of violence into something positive.

And now he's starting to use dehumanizing rhetoric, all these groups who live like vermin.

And this is what the original fascists did.

Hitler started talking about Jews as parasites in 1920.

So by the time he got in 1933, Germans had been exposed to this dehumanizing rhetoric for 13 years.

And Mussolini literally talked about rats.

After he had become dictator in 1927, he said, we need to kill rats who are bringing infectious diseases and Bolshevism from the east.

And so this matches up with Trump talking about immigrants bringing disease and other such things.

So this is very dangerous rhetoric with a very precise fascist history.

AMNA NAWAZ: Ruth, we have seen him and heard him previously mimic other Nazi propaganda.

He previously referred to undocumented immigrants as poisoning the blood of our country.

My team and I ran a very preliminary search.

And we could not find, in the last several years, he's been on a national stage, Mr. Trump using that kind of language before.

Is this a hardening and a ramping up of that language?

And why do you think we're seeing that now?

RUTH BEN-GHIAT: Yes, so he -- as I said, there's a two-part thing that authoritarians do.

First, they change the view of violence.

And Mr. Trump, since 2015, he started saying at his rallies, using his rallies and campaign events for radicalizing people.

And he started saying, oh, in the old days, you used to hurt people.

The problem is, Americans don't hurt each other anymore.

So now he's going into a new phase of openly dehumanizing his targets so that will lessen the taboos in the future.

And we see that, in 2025, he's got plans for mass deportations, mass imprisonments and giant camps.

So you need people to be less sensitive about violence, either committing it themselves or tolerating it.

And I see that as his -- the reason he's using this dehumanizing rhetoric now, to prepare people.

AMNA NAWAZ: He also called himself in those remarks a very proud election denier.

It's been three years since he lost that 2020 contest.

And we know he's still not conceded.

And we know also where the majority of Republicans and Republican-leaning voters stand in recent polls as recently as August; 69 percent of Republicans and Republican leaders say that Mr. Biden's win was not legitimate.

So, Ruth, what's the resonance of that lie and also the fact that Mr. Trump is embracing that now, saying he's very proud to be an election denier?

RUTH BEN-GHIAT: This is part of being much more overt about becoming an authoritarian and transforming America into some version of autocracy, because the endgame of election denial is actually to convince Americans that elections shouldn't be the way they choose their leaders, they're too unreliable.

And we're beginning to see this with his allies.

Michael Flynn said we shouldn't -- elections, we might not even have one.

Tommy Tuberville, the senator, said let's not even have elections, or the talk about America is never -- pure democracy doesn't work.

All of this is part of a campaign of, you could call it mass reeducation of Americans to want forms of authoritarian rule that Trump will give.

AMNA NAWAZ: Ruth, very briefly, if you can, we know we have heard from Mr. Trump's defenders in the past that you should not take what he says literally, that he often speaks off the cuff.

What do you make of that?

RUTH BEN-GHIAT: In all cases of history that I have studied in my book "Strongmen," people did not take the various Hitlers and Mussolinis seriously until it was too late.

AMNA NAWAZ: That is New York University historian Ruth Ben-Ghiat joining us tonight.

Ruth, thank you for your time.