The Justice Department charged Stone in January with obstruction, false statements and witness tampering in a 24-page indictment that cites the 1974 crime drama.

Stone, who was indicted in January on charges including witness tampering, says the clip will make him out to be a "murderous mafioso." The Justice Department calls the video "directly relevant to the charge."

"I kept saying Michael Corleone did this, Michael Corleone did that, so I said, yeah, sure," Pentangeli says, downplaying his earlier comments, in which he accused Corleone of crimes.

"I don't know nothing about that," Pentangeli says in response to a question about Corleone's connections to organized crime. "Oh — I was in the olive oil business with his father but that was a long time ago."

The video shows Corleone family mob leader Frank Pentangeli lying to Congress — and abandoning his plans to incriminate Michael Corleone — during a dramatic hearing in which Corleone makes an appearance in the audience.

The conservative provocateur and the Department of Justice have been sparring for a month over whether jurors can be shown a 4-minute-and-20-second clip from the film.

Longtime Republican strategist and former Trump campaign advisor Roger Stone wants a clip from "The Godfather Part II" to sleep with the fishes — at least during his upcoming trial.

"On multiple occasions," the indictment says, Stone told associate Randy Credico to "do a 'Frank Pentangeli' before [the House intelligence committee] in order to avoid contradicting" him.

One day in 2017, the indictment alleges, Stone also told Credico: "If you testify you're a fool. [...] I guarantee you you are the one who gets indicted for perjury if you're stupid enough to testify."

In July, the Justice Department asked Judge Amy Berman Jackson to show jurors the clip in order to reveal "what Stone intended to communicate."

The government's brief, filed in U.S. District Court in Washington, cites an email from Stone to Credico in 2018 in which Stone mimics Pentangeli's language from the scene.

"'Sure I know Roger Stone. he was in the Olive Oil business with my father. But that was a long long time ago. So I told them Roger Stone this, Roger Stone that. You should do Pantagela [SIC] on Erin Burnett," the email said, according to the Justice Department. Burnett is an anchor on CNN.

In response, Stone's attorneys filed a brief Aug. 9 in which they argued that showing the clip will "instantly create a connection in the minds of the jurors that Stone is somehow similar to a murderous mafioso."

Federal courts allow evidence to be excluded if it is likely to mislead or confuse the jury.

"Once the door is opened with a movie clip, which no doubt will accompany an explanation of why it is being played, the trial detours to a Mafia trial and Stone's connection to it, with all of its history and folklore," attorney Bruce Rogow wrote in the brief.

"A fictional demonstration of Mafia intimidation does so much more than the government's purported explanation of context, seeks to introduce. Its introduction is harmful to a fair trial. But introduction of the movie does more," Rogow wrote.

He wrote that showing the clip would also implicate Credico, a conservative comedian and activist, by suggesting he was an "organized crime figure" like Pentangeli, who "understood the threats in the same way as the fictional character in the movie understood it."

"As opposed to the message which was a joke between friends, or a suggestion to follow [Credico's] lawyer's advice and remain silent. It implies that Stone kidnapped [Credico's] brother (if he has one) and kept him hostage. It implies that [Credico] is in a witness protection program like Pentangeli, who has to reside at an Army barracks because of the threat to Pentangeli's safety," Rogow wrote. "It makes Roger Stone the Michael Corleone character in this analogy — an iconic violent godfather of the Mafia."

In response to a request for comment, Rogow said in an email: "The filings speak for themselves."

The battle continued on Friday, when the Justice Department responded to Stone's brief by arguing that the government "does not intend to suggest that Stone is an organized crime figure."

Jessie Liu, the U.S. Attorney for the District of Columbia, noted that Jackson could warn jurors that "the clip should not be taken to suggest that Stone is in the mafia" or "planned a murder."

"The movie clip itself powerfully illustrates both the clarity of the references to the scene in Stone's messages and the obvious parallels between the congressional investigation depicted in the film and the congressional investigation that gave rise to [Credico's] subpoena," Liu wrote in the five-page brief.

— CNBC's Dan Mangan and Kevin Breuninger contributed to this report.