Appearing as a guest on Thursday's CNN Newsroom with Carol Costello, CNN political analyst David Gergen worried that the Republican party has "turned right," and that GOP presidential candidate Donald Trump is "doubling down" by choosing Steve Bannon of Breitbart News as CEO of his campaign.

The CNN host even managed to work in a Hitler reference as he picked up on Breitbart founder Andrew Breitbart supposedly comparing Bannon to film maker Leni Riefenstahl, who was a leading propagandist for the Nazi dictator. As if Bannon were similar to a Nazi, Gergen fretted:

I just can't emphasize enough, what we have seen in the reshuffling that Trump is reaching out to people who are bigger bomb throwers than he is, that, who think Fox News is way too tame, that, you know, Mr. Breitbart has called Mr. Bannon -- who's the new guru of the Trump campaign -- he's called him the Leni Riefenstahl of the American Tea Party.

He added:

People who know history understand Leni Riefenstahl was the woman who was the chief propagandist for Hitler. And here, one of his friends, Breitbart, is calling Bannon that kind of person.

A bit earlier in the segment, after host Carol Costello brought up Republican speech writer Richard Cross announcing he will vote for Hillary Clinton, Gergen declared:

I think he's a symbol of a growing number of Republicans who are moderates. He's a self-described moderate, and he feels increasingly uncomfortable in a party that's turned right. And basically, I think, speaks for a lot of people in the sense of saying, "I no longer have a home," you know, "My Republicans pals think that I'm a renegade, and my Democratic friends don't know what to make of me."

A bit later, he added:

But, if in fact, what this reshuffling of the Trump team means he's going to go even further right and going to go and engage in even more incendiary attacks against the media, against Muslims, you know, against women, against anyone and whatever, you know, that these people are going to -- there's going to be a bigger flood, you know, because as much as people don't want Hillary, they also feel, "Look, if I can't vote for this guy, who can I vote for? I'll throw away my ticket, I throw away my vote if I vote for the Libertarian."

Below is a transcript of the relevant portion of the Thursday, August 18, CNN Newsroom with Carol Costello:

CAROL COSTELLO: Donald Trump's new team is promising a bare-knuckled fight where no tactic for taking down Hillary Clinton will be off limits. It may work -- or not -- but one thing is clear: Many high-profile Republicans are disavowing Trump and going with her. The latest is Richard Cross, who drafted one of the most moving speeches at the Republican National Convention for the Benghazi mom, Patricia Smith.

PATRICIA SMITH, MOTHER OF BENGHAZI VICTIM, CLIP #1: I blame Hillary Clinton personally for the death of my son. That's personally.

SMITH CLIP #2: Donald Trump is everything Hillary Clinton is not.

SMITH CLIP #3: He will make America stronger, not weaker. This entire campaign comes down to a single question: If Hillary Clinton can't give us the truth, why should we give her the presidency?

COSTELLO: Now, Cross helped write those powerful words, but now he says he cannot vote for Trump. He will vote for Clinton. ... So let's talk about this. David Gergen is here. He's a CNN senior political analyst and a former presidential advisor to Nixon, Ford, Reagan and Clinton. ... So Richard Cross, he writes this powerful speech for this Benghazi mother, and now he says he cannot vote for Trump. What do you make of that?

DAVID GERGEN, CNN POLITICAL ANALYST: I think he's a symbol of a growing number of Republicans who are moderates. He's a self-described moderate, and he feels increasingly uncomfortable in a party that's turned right. And basically, I think, speaks for a lot of people in the sense of saying, "I no longer have a home," you know, "My Republicans pals think that I'm a renegade, and my Democratic friends don't know what to make of me."

And I can just tell you that there are lots and lots of people in America who feel that way, who feel uncomfortable in the Republican party. They have been hoping that they could see signs in Donald Trump that he would move more and that he would pivot toward their direction and that he would moderate, he would stop some of these attacks that he's been doing.

And now, Carol, the truth is, what he has just done here this week in hiring Mr. Bannon and bringing Roger Ailes into the midst of his campaign, you know, he's doubling down, as you know, I think what we're seeing in Mr. Cross is the early part of the flow. I think if what we see is Trump being even more Trumpian, it's going to trigger a bigger exodus of people like Mr. Cross, the moderates who feel homeless.

COSTELLO: But don't Republicans -- don't Republicans in general like attacks on Hillary Clinton? They want Donald Trump to focus on Hillary Clinton and to attack her?

GERGEN: Oh, I do think that they -- there's a lot of Hillary Clinton sentiment among moderates in the Republican party. That's why Mr. Cross has been so, you know, he's agonizing about what to do. I think he's -- I think basically at the end of his article he said he was going to vote for Hillary.

But, if in fact, what this reshuffling of the Trump team means he's going to go even further right and going to go and engage in even more incendiary attacks against the media, against Muslims, you know, against women, against anyone and whatever, you know, that these people are going to -- there's going to be a bigger flood, you know, because as much as people don't want Hillary, they also feel, "Look, if I can't vote for this guy, who can I vote for? I'll throw away my ticket, I throw away my vote if I vote for the Libertarian."

And that's why Cross is going to go, I think, for Hillary in the end and, but, listen, I just can't emphasize enough, what we have seen in the reshuffling that Trump is reaching out to people who are bigger bomb throwers than he is, that, who think Fox News is way too tame, that, you know, Mr. Breitbart has called Mr. Bannon -- who's the new guru of the Trump campaign -- he's called him the Leni Riefenstahl of the American Tea Party.

People who know history understand Leni Riefenstahl was the woman who was the chief propagandist for Hitler. And here, one of his friends, Breitbart, is calling Bannon that kind of person. And, you know, just read the accounts of what Breitbart has been saying and say, "Do you really think that suburban moms, educated women are going to -- people with college degrees are now going to move over and vote for Trump happily?" No, they're going to be looking at Mr. Cross and saying, "I wonder if I should be doing the same thing."