(WASHINGTON) — Both Joe Biden and Donald Trump may well earn enough delegates to clinch the nominations for their respective parties on Tuesday, when four states and one territory will report election results.

Should Trump be able to mathematically cross the Republican National delegate threshold then, the 2024 Republican race would be one of the shortest highly contested presidential primaries since the modern nomination process took shape in the 1970s.

Biden and Trump becoming the presumptive presidential nominees will also officially begin a nearly eight-month-long general election battle that has, in some ways, already been underway for several weeks.

The rematch between the president and former president is expected to revolve around the same swing states and similar issues as in 2020, with Biden arguing that Trump is an anti-democratic candidate who would pull the country back from its progress and erode rights like abortion access, corruption the nation’s “soul” — as Trump, running again on a MAGA message, hammers Biden over high inflation and immigration and contends his style would ensure more stability.

But first, both candidates have to finish winning their nominations, which is done by earning delegates based on the amount of votes they receive.

Presidential primary elections are being held in three states on Tuesday: Georgia, Mississippi and Washington. Hawaii will hold its GOP caucuses after earlier holding its Democratic caucus.

Biden could be declared the presumptive nominee first, after polls close in Mississippi at 8 p.m. EST.

For Democrats, 254 delegates are at stake on Tuesday. Thus far, Biden has won 1,868 delegates (including six allocated earlier in the day from the Northern Mariana Islands) according to ABC News’ current estimate. To win the nomination, 1,968 delegates are needed — and Biden just needs to win 100 more delegates to reach that threshold.

The earliest Trump could mathematically be declared the presumptive nominee is after polls close in Washington state later in the night, at 11 p.m. EST.

A Republican candidate needs to earn 1,215 delegates to earn the party’s nomination. Trump had 1,078 delegates heading into Tuesday’s round of contests, according to ABC News’ current estimate, so he needs 137 more to cross the threshold.

For Republicans, 161 delegates are up for grabs on Tuesday.

Trump’s last major remaining rival for the GOP nomination, former U.N. Ambassador Nikki Haley, suspended her campaign one day after Super Tuesday last week, when she lost 14 contests but won the Vermont primary. Haley had also won the Washington D.C. contest, which put her at 91 delegates earned, according to ABC News estimates.

Florida Gov. Ron DeSantis and tech entrepreneur Vivek Ramaswamy also have a small share of delegates, both from Iowa’s GOP caucuses, the only contest each participated in before they suspended their primary campaigns. DeSantis has nine delegates and Ramaswamy has three.

Both the Democratic and Republican nominations will officially be awarded at their party conventions this summer, in August and July, respectively.

Biden’s path to his nomination has faced fewer challengers than Trump did, though he has been running against long shot candidates including author and speaker Marianne Williamson, who also ran in 2020, and Minnesota Rep. Dean Phillips.

Neither of them has won delegates. Williamson suspended and then unsuspended her campaign, while Phillips, who ran against Biden by arguing that the president is too old and too weak against Trump to seek another term, left the race after Super Tuesday.

Biden’s only loss in a nominating contest so far has been in American Samoa, when little-known entrepreneur Jason Palmer beat him, 51 votes to 40.

More notably, an anti-Biden “uncommitted” campaign protesting his stance on Israel’s war against Hamas in Gaza has had some success in a few states after being launched in Michigan in February.

To date, the uncommitted option is estimated to have earned 20 delegates total from Hawaii, Michigan and Minnesota.

Washington is the only state with an uncommitted option on their ballot on Tuesday. In Georgia, however, some anti-Biden organizers have initiated a “Leave It Blank Primary Campaign” that encourages Democrats to request a ballot but submit it without choosing Biden or another candidate as a vote.

Democrats abroad, whose voting ends Tuesday, are also able to cast their ballots for an uncommitted option.

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