This year’s primary season concluded more quickly than usual, due to Mr Trump’s dominance of the Republican race – winning by significant margins in all of the early voting states of Iowa, New Hampshire, Nevada and South Carolina.
Although incumbent presidents usually win the nomination of their party without serious challengers, the party in opposition usually sees a contest between candidates who have not served in the White House.
Mr Trump is the second president in US history to be ousted from office and return at a future election, giving him the status of a de-facto incumbent.
Mr Biden and Mr Trump’s early status as presumptive nominees will increase pressure on the President to debate his predecessor before the scheduled presidential television debates in the autumn.
Mr Trump has already called for an event to be organised, and said he would attend even if it was run by the “corrupt” Democratic National Committee.
The latest polling suggests that Mr Trump is currently winning in the key battleground states of Michigan, Pennsylvania, North Carolina, Georgia and Arizona. If an election was called immediately, he would likely win it.
However, the former president must first navigate a series of criminal trials, some of which are scheduled to begin before polling day on November 5.
The first of the cases, over allegations of falsifying business records relating to the porn star Stormy Daniels, is set to begin in New York on March 25.
Mr Biden is facing poor ratings in national opinion polls, with voters reporting that they think he is too old to serve again, and that they have felt the impacts of persistent inflation in the US.
