Ben Carson likes to talk about Adolf Hitler and the Nazis. A lot.

Nazi comparisons, of course, are a staple of politics. Often, the metaphor-maker will quickly back off said metaphor. Carson, though, in both his volume of Nazi comparisons and his refusal to back down from them, is the exception. He simply doesn't shy away from holding up Nazi Germany as a dire warning of the slippery slope America is on.

On Thursday, the Republican presidential candidate drew on the familiar verbal instrument to illustrate why he's against more gun control. In the days after the deadly Oregon school shooting, Carson said taking away people's guns means taking away their freedoms, and he suggested an armed German citizenry would have avoided the Holocaust.

Carson talks about Hitler on the campaign trail so much that his campaign is apparently trying in vain to get him to stop. Campaign manager Barry Bennett told ABC News they'd rather Carson find another go-to-analogy. Bennett, though, explained it's really not Hitler that Carson keeps talking about, but rather "how a general population kept their mouth shut.” Bennett at the same admitted that Carson has been talking about Hitler for years to make his case. 

And indeed, Carson has. In fact, there are at least a dozen instances.

The early days

1. A cautionary tale for America

The liberal-leaning site Think Progress reported that in 2009, Carson was accepting an honorary degree from Lafayette College alongside a Holocaust survivor. He used the opportunity to warn graduates to "speak up" to avoid a similar tragedy in America.

“What happened in Nazi Germany? I dare say the vast majority of German people did not believe what Hitler believed. But they didn’t speak up, and you see what the result was."

2. It could happen again

Carson earned conservative star power and presidential buzz when he criticized President Obama at a 2013 National Prayer Breakfast with the president sitting just a few feet away. In his subsequent public appearances, the Nazi references seemed to pick up.

At a Jan. 31 fundraiser in Oregon, the then-Fox News commentator repeated his calls to "stand up" against tyranny, the Huffington Post first reported

"There comes a time when people with values simply have to stand up. Think about Nazi Germany. Most of those people did not believe in what Hitler was doing. But what did they speak up? Did they stand up for what they believe in? They did not, and you saw what happened. And if you believe the same thing can't happen again, you're very wrong."

3. Creeping Nazism

A few months later, Carson received a standing ovation in a standing-room-only crowd listening to him speak at a March 2014 event in New York. After the claps and cheers subsided, the conservative Web site reported, "Carson said the current state of our government and institutions are 'very much like Nazi Germany:'"

“You had the government using its tools to intimidate the population. We now live in a society where people are afraid to say what they actually believe.” He blamed in particular political correctness and government intimidation for the state of today's Nazi-like reality.

4. No dancing around it

In an August 2014 interview with The Washington Post, reporter Ben Terris asked Carson if he worried whether comparing Obama supporters to Nazi sympathizers might be "something a bully would do." Carson replied:

"You can’t dance around it. If people look at what I said and were not political about it, they’d have to agree. Most people in Germany didn’t agree with what Hitler was doing. ... Exactly the same thing can happen in this country if we are not willing to stand up for what we believe in.”

5. Read 'Mein Kampf' to understand today's society

In a September 2014, interview with Newsmax, Carson suggested parallels between "The Naked Communist," a 1958 book suggesting communists plot to take over the world, and today's society. "It reads like it was written last year," Carson said, also suggesting people read  Hitler's manifesto, "Mein Kampf," telling people to read and draw their own parallels about the nation we live in.

Carson's books

The Daily Beast combed through Carson's written works to find more references.

6. Tying socialism to Hitler

His 2014 book, "America the Beautiful," contains this call to action, according to Daily Beast reporter Gideon Resnick:

“But are you willing to surrender your precious liberties to a socialist state which promises ‘security’ for everyone and government-enforced equality? Isn’t this what Hitler and other socialists promised the German people in his Nazi (national socialist) platform -- a country in which government guarantees security and ‘equality’ in exchange for giving up individual freedom? Will Americans fall for the same scam?"

7. An early reference to guns

Carson's 2014 book "One Nation," has more, according to Resnick:

"One can only wonder what would’ve happened if people had not tolerated the foolishness of Adolf Hitler’s appeal to the baser instincts of greed and envy and his institution of an official weapons confiscation program.”

On the campaign trail

According to news reports, Carson repeated the metaphor three times in a little more than a week.

8. 'It can happen here'

At a church in North Carolina, ABC News reported he said:

“I’ve talked in the past about how the people in Nazi Germany did not agree with Hitler. A lot of them didn’t. But did they stand up? Did they say anything? No, they kept their mouths shut and look at the atrocities that occurred. And some people think something like that can’t happen here but think again. Look at the world and all those examples of tyranny. It can happen here.”

9. It can really happen here

At a Sept. 30 campaign event in New Hampshire, CNN reported Carson begged "to differ" with critics who say a Nazi Germany could never befall America:

 "If you go back and look at the history of the world -- tyranny and despotism and how it starts -- it has a lot to do with control of thought and control of speech."

10. I'll say it again

In his news conference afterward, Carson doubled down:

"If people don't speak up for what they believe, then other people will change things without them having a voice. Hitler changed things there, and nobody protested. Nobody provided any opposition to him, and that's what facilitated his rise."

A reporter asked who in America is most like Hitler. "I'm not going to go into that," Carson said.

Another reporter pressed Carson on whether he was comparing President Obama to Hitler: "No," he said, shifting to talk about the problem with political correctness: "In a situation where people do not express themselves, bad things can happen. That's the main problem I have with political correctness."

11. Planned Parenthood

In August, Carson responded to a question on local Nevada TV show Nevada Newsmakers about whether he saw similarities between Planned Parenthood and Nazi Germany. Carson said he did (more on this here):

“I certainly see a connection in the sense that Margaret Sanger, their founder, and people like Adolf Hitler … felt there were certain people who were superior and certain people who were inferior. And the way that you strengthen the society was to enhance superior ones and eliminate the inferior ones.”

12. Purposely provocative

Most recently, Whoopi Goldberg asked Carson what he meant by "Hitler-Nazi Germany could happen here" in his Tuesday appearance on "The View."

Carson first said, "That's not what I said. That's the spin." He went on: "I purposely said that because I knew the left wing would go crazy: 'He said Hitler!'" Then he elaborated:

"So what I said is most of the people in Nazi Germany did not believe in what Hitler was doing. But did they speak up? No. They kept their mouths shut. And when you do that, you are compromising your freedom and the freedom of people who come behind you. You have to be willing to stand up for what you believe in."

13. Defending his gun control = tyranny argument

In response to his comment Thursday that the Holocaust could have been avoided if the Germany people were armed, the Anti-Defamation League condemned his comments as "historically inaccurate." Carson called that "foolishness" in an interview with Good Morning America's George Stephanopoulos:

“I’d be happy to discuss that in depth with anybody but it is well known that in many places where tyranny has taken over they first disarm the people. There’s a reason they disarm the people. They don’t just do it arbitrarily.”

Carson, as he often does, is trying to have it both ways. He's not comparing the United States to Nazi Germany; he's just repeatedly warning that a certain set of circumstances that currently exist here are somewhat similar to what happened in 1930s Germany.

And you can bet he'll keep saying it.