Donald Trump spent his last moments as President sad and alone, according to Jim Acosta, who led CNN's coverage of Trump during his presidency.
In his farewell to Washington on Wednesday morning, Trump 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 CNN's Chief Media Correspondent Brian Stelter on "Reliable Sources" on Sunday. "I've never seen him this alone the entire time he was at the level of presidential politics."
Acosta, now CNN's lead domestic reporter, said Trump may have had a different outcome at the end had he not instigated a riot that laid siege to the US Capitol on January 6 -- one of several attempts in the waning days of his presidency to overturn the election results. After the siege, Trump lost whatever remaining credibility he had with many of his supporters, according to Acosta.
"Essentially what we saw was the undoing of the Trump presidency," Acosta said of Trump's final days. "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 of unraveled at the end."
After the Capitol riot, Trump was banned from Twitter, and he has largely remained out of public view save for a few short video messages and his last address to supporters at Joint Base Andrews. It's an unusual quiet period for Trump, who has relished the spotlight for decades.
Outside the White House, the daily media scrutiny of Trump will almost certainly fade. Stelter noted major media outlets, including Fox, are not stationing reporters in Palm Beach, Florida, to cover Trump.
Acosta expects Trump won't be able to remain silent for long.
"I think it is temporary," he told Stelter. 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."
But with record-low popularity in the last days of office, Trump probably doesn't have the ability to lead a major political party and win back the presidency, Acosta noted -- and that's if the Senate in its upcoming impeachment trial fails to convict Trump and prevent him from running for office again.
Trump likes to compare himself to Grover Cleveland, who remains the only president to serve two non-consecutive terms. But Grover Cleveland was more popular than Trump when he won his second term, Acosta noted.
"Trump isn't going to be able to do that right now," he predicted.
Acosta had a combative relationship with the Trump White House that at one point took away his credentials -- a decision that CNN successfully sued to overturn in court.
Although Trump is out of office, Acosta still calls him "lord of the lies" and believes he should not be ignored.
"While he's still licking his wounds down in Mar-a-Lago, he poses a threat to this country," Acosta said.
"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."