Acosta, who spent the past four years covering the Trump White House for CNN, told Brian Stelter on Sunday that closest allies and advisers abandoned Trump at the end.
"It was sort of a sad and pathetic sight. I've never seen him this alone the entire time he was at the level of presidential politics," the reporter said.
It took more than two months for Trump to accept Biden's victory in the 2020 presidential election.
After launching dozens of legal challenges in states across the nation, all of which were rejected by the courts, he held a rally in Washington, D.C. urging his supporters to prevent the U.S. Congress from certifying Electoral College votes.
Convinced that they would be able to do so, they clashed with security forces at the U.S. Capitol and managed to storm and vandalize the building. This doomed Trump's political future and ruined his legacy, according to Acosta.
"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 of unraveled at the end."Both Democrats and Republicans condemned the former commander-in-chief for inciting the riots. Virtually all major social media platforms, including Twitter, suspended his accounts.
On January 20, as Biden was preparing to take office, Trump flew to Palm Beach, Florida and he hasn't made extensive public comments since.
According to Acosta, however, the silence is temporary. The reporter said that he expects the former president to stage a comeback because he can "lead at least a fringe movement in this country."
Still, Acosta continued, Trump left office with a low approval rating so it is unlikely that he will be able to launch a successful presidential bid in four years.
This does not mean that he should be ignored, Acosta said, because "while he's still licking his wounds down in Mar-a-Lago, he poses a threat to this country."
A poll from the non-partisan Pew Research Center released last week found that Trump left office with the lowest job approval rating of his presidency. In the survey, only 29 percent of respondents said that they approved of the job he did as commander-in-chief.
For a while, Trump reportedly explored forming a third party but he seems to have abandoned that idea.