US President Joe Biden and his predecessor Donald Trump passed the delegate threshold to win each party’s nomination.
They all crossed the finish line winning some states in Tuesday’s primaries.
These two candidates in 2020 will be his first rematch in the US presidential election in 70 years.
Polls suggest a close race in some key states.
Candidates will be formally announced at the party’s convention this summer.
The 81-year-old president said Tuesday night that he was “honoured” by voters’ support for his re-election “at a time when the threat from President Trump is greater than ever.”He pointed to positive trends in the economy and said the United States is “in the midst of a comeback,” but faces challenges to its future as a democracy and concerns from those who want to pass abortion regulations and cut social programs.
He claimed that he was facing challenges.”We believe the American people will continue to choose to move our country forward,” Biden said in a statement from his campaign.
As an incumbent, Mr. Biden has a natural advantage and faces no serious challenger for the Democratic nomination.
The party machine rallied behind him despite persistent concerns among voters that his age limited his ability to carry out the duties of the presidency.
Meanwhile, Mr Trump, 77, continues to enjoy popularity with Republican voters, which has helped him win one primary election after another over his well-funded rivals.
His campaign for a second term in the White House focused on toughening immigration laws, including promises to “close the border” and implement “record” deportations.