CNN's Jim Acosta says that former President Donald Trump will likely continue to lead a movement across the United States despite no longer being commander in chief.

What are the details?

During a Sunday appearance on CNN's "Reliable Sources," Acosta told Brian Stelter that he believes the former president's quietude since leaving the White House is only transitory and signifies more to come.

"I think it is temporary," he told Stelter, according to a report from the network. "The populist political forces that sent Trump to the White House 'have the potential to come back in the days to come.'"

"I do think Trump is going to lead at least a fringe movement in this country," Acosta added.

Elsewhere during the discussion, Acosta warned that the former president — who he referred to as "lord of the lies" — should not yet be counted out.

"While he's still licking his wounds down in Mar-a-Lago, he poses a threat to this country," Acosta explained. "This is not a time to put away our fact-checkers in some sort of box on a shelf. They're going to be needed to fact-check this movement. Trump may be going away, but Trumpism is not."

Trump's final days in office

Acosta, who heavily covered the Trump White House during the former president's administration, said that Trump spent his final days in office alone.

The outlet reported that the former president "greeted a small crowd of about 200 at Joint Base Andrews before he boarded Air Force One with family and the press, including Acosta."

"It was sort of a sad and pathetic sight," Acosta told Stelter. "I've never see him this alone the entire time he was at the level of presidential politics."

Of the former president's final days, Acosta said, "Essentially what we saw was the undoing of the Trump presidency. What we saw the president build over the course of four or five years out on the campaign trail and over at the White House just sort of unraveled at the end."

What else?

Last week, the Wall Street Journal reported that Trump is looking to form his own political party, dubbed "The Patriot Party."

Having reportedly spoken to confidantes and aides preceding his White House departure, Trump is said to believe that many Republicans abandoned him following the early January attack on the U.S. Capitol.

"Trump discussed the matter with several aides and other people close to him last week," the outlet reported. "The president said he would want to call the new party the 'Patriot Party,' the people said."

In a Tuesday farewell video, Trump said that his movement is "only just beginning."

"As I prepare to hand power over to a new administration at noon on Wednesday, I want you to know that the movement we started is only just beginning," he said. "There's never been anything like it. The belief that a nation must serve its citizens will not dwindle but instead only grow stronger by the day. As long as the American people hold in their hearts deep and devoted love of country, then there is nothing this nation cannot achieve."

In his final speech as president, Trump at Joint Base Andrews said, "We will be back in some form."