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Stephen Colbert roasted Herman Cain and his 9-9-9 plan on his TV show Thursday night with a fictional movie clip of an actor playing Hitler slamming a table and screaming, “Nein! Nein! Nein!”

Nein rhymes with nine, but it means “no” in German. The clip comes from the 2009 Quentin Tarantino movie “ Inglorious Bastards.”

The moment in Colbert’s show was brief and came amid a longer piece about Herman Cain’s controversial idea to build a deadly electrified fence across the U.S. border. Cain has waffled on the proposal, at first saying he was joking, then apologizing for its insensitivity but not exactly retreating from it. Colbert later used an image of Cain and Hitler next to each other.

“Electrified fence,” said Colbert. “Classic joke.  It’s like, ‘Who’s on first, what’s on fire?’ I don’t know. How many people has it killed?

“But the real punch line of the joke is that it’s not a joke,” said Colbert, playing a clip of Cain sort of walking back the statement. “He’s joking unless you’re into the idea, in which case he means it.”

Watch the clip at Colbert’s Comedy Central website.

Colbert  has made the rights of migrant workers a cause and testified on the subject least year on Capitol Hill.    Colbert broke sarcastic character once during his testimony. He was asked at the hearing by Rep. Judy Chu, D-Calif., why he chose this issue.

“I like talking about people who don’t have any power. And this seems to be [about] people without any power,” he said, arguing that migrant workers “don’t have any rights.

“We invite them here and ask them to leave,” he said.

But the use of Hitler for any sort of comparison is generally verboten in American politics and popular culture.

ESPN recently fired country music star Hank Williams, Jr., after he seemed to compare President Obama to Hitler. The fashion designer John Galliano was fired by Christian Dior after being recorded praising Hitler.

Certainly, the rules are different for a comedy show. Colbert often uses Hitler to make a point. Check out the number of clips tagged “Adolf  Hitler” on his website.

Back in January, following the shooting of Rep. Gabrielle Giffords, D-Ariz., Colbert jokingly called President Obama Hitler before praising his speech in Tucson after the shooting. Colbert joked that by calling Obama Hitler and praising the speech he had found a way to praise Hitler.

But Colbert’s Comedy Central colleague, Jon Stewart, has lambasted lawmakers from both parties for using Nazi analogies, especially in the wake of the Giffords shooting, devoting a large portion of several shows during a week in January to it.

Colbert’s ironic comedy, beneath his character, usually seems to have a point. In calling Obama Hitler to praise his speech, Colbert seemed to really be praising the speech. Whereas, in using the clip from “Downfall,” he really seemed to be criticizing Cain.

He has a SuperPac that airs ironic TV ads, apparently to make a point about the ability of anonymous donors to influence politics. This week, the organization released an advertisement about the NBA lockout.

Read more about Colbert’s SuperPAC .

An email to Colbert’s spokesperson was not immediately returned.

*This post originally misidentified the move clip as the 2004 German movie “Downfall.”