Actor Robert De Niro, in case you didn’t know, is also a constitutional scholar.

The “Goodfellas” star thinks President Trump will flout the Constitution because he will “likely start a war” in order to stay in the White House for 12 years.

“He’s going to be history at one point, though he’d love to be president for life,” De Niro recently told The Daily Beast. “He jokes about it. I think that if he became president for a second term, he’d try to have a third term, and let smarter people manipulate it into getting us into some kind of altercation: a war.”

The presidential historian bloviated on. “The only other president who served a third term was [Franklin D.] Roosevelt because he was in a war, and this fool would go and start something. This was what [film director] Marty Scorsese was saying, and I said, ‘Marty, I never thought of that. I never thought he’d go for a third term if there was a war or something,’” De Niro said.

CNN’s S.E. Cupp, who hosts a weekend show called “Unfiltered,” recently took to Twitter to pass along the theory that Trump will try to demand a third term.

“Remember when [New York City Mayor Michael R.] Bloomberg demanded a third term as mayor and got it?” she asked her 415,000 followers. “Trump will do the same. Beware, the same autocratic impulses “

And Trump-hating director Michael Moore said much the same thing earlier this year. (It’s interesting that the liberals who spout these conspiracy theories are all giving Trump at least another term, warning that the problems only begin when he tries to snatch a third term.)

Last June, Trump fed the fires.

“The good news is that at the end of 6 years, after America has been made GREAT again and I leave the beautiful White House (do you think the people would demand that I stay longer? KEEP AMERICA GREAT),” he tweeted.

The conspiracy theory has exploded since Trump ordered an airstrike to take out the world’s No. 1 terrorist, Qassem Soleimani, a major general in Iran’s Islamic Revolutionary Guard Corps and commander of its Quds Force, a division responsible for extraterritorial military and clandestine operations.

De Niro, it’s worth pointing out, starred in a movie called “Wag the Dog,” about a president, seeking reelection, who faces scandal and is extricated by declaring war against Albania. The film was released a month before news of President Clinton’s affair with Monica Lewinsky broke — when Clinton initiated two anti-terrorism bombing campaigns in the subsequent year of impeachment. Some wags in the media said the embattled president was trying to “wag the dog.”

So now, with Trump mired in his own impeachment furor, speculation is swirling that he, too, is trying to wag the dog.

Even though tensions between the U.S. and Iran have quieted in the last few days, Trump is well aware of the strategy, designed to bring about a swell of national pride and a “rally ‘round the flag” effect that could help an incumbent (although the effect is usually short lived).

During President Obama’s tenure, Trump repeatedly predicted that Obama would attack Iran in order to help him get reelected. He first warned about such a nefarious plan in 2011, tweeting that Obama “will attack Iran in the not too distant future because it will help him win the election.”

“@BarackObama will attack Iran in order to get re-elected,” Trump tweeted in January 2012. In July, he tweeted: “Just as I predicted, @BarackObama is preparing a possible attack on Iran right before November.” Right before the election, he tweeted: “Don’t let Obama play the Iran card in order to start a war in order to get elected — be careful Republicans!”

While Obama could have been — “could have been” — trying to start a war with Iran to win election (a spurious theory at best), what the amateur constitutional scholars like De Niro and Ms. Cupp and Moore don’t seem to know is that Trump can’t start a war to secure a third term.

There’s something called the 22nd Amendment, which says a person can only serve two elected terms as president.

“No person shall be elected to the office of the President more than twice, and no person who has held the office of President, or acted as President, for more than two years of a term to which some other person was elected President shall be elected to the office of the President more than once,” says the amendment, which was passed after Roosevelt had won third and fourth terms, a move that broke custom but no constitutional limit at the time.

End of story.

Will someone please let De Niro know?

*Joseph Curl ran the Drudge Report from 2010 to 2014 and covered the White House for a dozen years. He can be reached at josephcurl@gmail.com and on Twitter at @JosephCurl. A version of this article ran previously in The Washington Times.