A confidant of Donald J. Trump who is likely to serve in a senior national security role in any new Trump administration threatened on Tuesday to target journalists for prosecution if the former president regains the White House.

The confidant, Kash Patel, who served as Mr. Trump’s counterterrorism adviser on the National Security Council and also as chief of staff to the acting secretary of defense, made the remarks on a podcast hosted by Stephen K. Bannon, Mr. Trump’s former strategist, during a discussion about a potential second Trump presidency beginning in 2025.

“We will go out and find the conspirators, not just in government but in the media,” Mr. Patel said. “Yes, we’re going to come after the people in the media who lied about American citizens, who helped Joe Biden rig presidential elections — we’re going to come after you. Whether it’s criminally or civilly, we’ll figure that out.” He added: “We’re actually going to use the Constitution to prosecute them for crimes they said we have always been guilty of but never have.”

Earlier in the interview, when asked by Mr. Bannon whether a new administration would “deliver the goods” to “get rolling on prosecutions” early in a second term, Mr. Patel noted that the Trump team had a “bench” of “all-America patriots,” but he said he did not want to name any names “so the radical left-wing media can terrorize them.”

A spokeswoman for Mr. Patel, Erica Knight, pointed out that in the same conversation with Mr. Bannon, Mr. Patel said they would “follow the facts and the law.” She also sent The New York Times a statement from Mr. Patel, reading, “When President Trump takes office in 2025, we will prosecute anyone that broke the law and end the weaponized, two tier system of justice.”

But Mr. Trump, who is facing 91 felony charges in four separate cases, has already promised to use the Justice Department to “go after” his political adversaries — signaling that a second Trump term would build on the ways it opened investigations into his enemies during his first term and fully abandon the post-Watergate norm of Justice Department independence.