The former president's aides are saying this announcement - and this campaign - will look more like 2016 than 2020, according to reports. Stripped of the powers of office, Mr Trump will frame himself as an outsider, seeking to disrupt a political establishment on the left and right that views him with hostility.
In 2016, despite seemingly long odds, Mr Trump first beat his Republican rivals and then narrowly defeated Democrat Hillary Clinton, who was seeking to win a third consecutive White House term for her party.
It was an improbable achievement but one that showcased Mr Trump's undeniable strengths as a candidate.
He has an unmatched sense of which issues are important to grass-roots conservatives. His unpredictable and inflammatory style can drive news coverage and deny the spotlight to his competitors. He has a base of loyal supporters and can motivate typically unengaged Americans to vote. And after four years in office, many of those supporters hold positions of authority within the Republican Party.
Even so, there's reason to believe the task ahead of him will be a daunting one. Here's why.