Biden and Trump clinch nominations, setting the stage for a grueling general election rematch

WASHINGTON -- President Joe Biden and former President Donald Trump have clinched the Democratic and Republican presidential nominations, respectively, after another round of voting on Tuesday, ABC News projects based on the ABC News delegate estimate.

That officially begins a nearly eight-month-long general election battle that has, in some ways, already been underway for several weeks. That follows one of the shortest highly contested presidential primaries since the modern nomination process took shape in the 1970s.

The rematch between Biden and Trump is expected to revolve around the same swing states and similar issues as in 2020, including immigration, the economy, and democratic values.

Abortion and reproductive access are also expected to be flashpoints along with inflation and foreign policy.

Democratic primary elections were held in three states on Tuesday: Georgia, Mississippi and Washington as well as in the Northern Mariana Islands and in voting by Democrats living abroad.

For Democrats, 254 delegates were at stake on Tuesday, and Biden needed to get 100 more in order to earn the 1,968 delegates needed to officially win the Democratic nomination this summer.

He tipped over the edge after the results of the Mississippi presidential primary were projected.

A Republican candidate needed to earn 1,215 delegates to also earn the GOP nomination awarded this summer.

Trump had 1,078 delegates heading into Tuesday's round of contests, according to ABC News' estimate, so he had to get 137 more to cross the threshold -- which he did when Washington reported its results. Overall, 161 delegates were up for grabs on Tuesday.

Because former U.N. Ambassador Nikki Haley, Trump's last major Republican opponent, continued to contest the GOP primary until Super Tuesday, the competitive period of this year's Republican contest ended up falling short of setting any records.

The current record for the earliest end date of a contested presidential primary is March 3 in the 2004 Democratic contest, and the lowest number of voting states is 19 in the 2000 Democratic race.