Explained: How The US Presidential Election Works

Americans head to the polls later this year in what will be a closely watched presidential election. 

Here is the way the process will play out between now, November's vote and next year's swearing-in.

Primaries

The voting calendar plays an outsized role in the country's long primary season as state-by-state contests commence this month. 

A clear winner will likely emerge by the spring -- meaning states that vote early can have more influence than states that vote later.

Republican voters in Iowa will have the first chance to whittle down the pack of White House contenders, on January 15, during that state's caucus. Though a caucus functions slightly differently than a primary, it will be the first contest in the race, shaping candidates' momentum going forward.

The Democratic Party will also host primaries, though President Joe Biden is running largely unopposed, with his challengers consisting of marginal political figures not expected to make serious inroads.

Official party nominations will not be doled out until the Republican and Democratic conventions, held in July and August, respectively. 

The general election is by law scheduled for the first Tuesday following the first Monday in November -- this year, November 5.

Trump legal troubles

The Republican primary will be complicated by frontrunner Donald Trump's legal entanglements, including lawsuits arguing he be stripped of his eligibility for holding office due to his role in the 2021 storming of the US Capitol.

Rulings in Colorado and Maine have banned the former president from those states' primaries under the Constitution's "insurrection clause."

The US Supreme Court will hear oral arguments in the Colorado case on February 8, with lawyers for Trump urging justices to reverse the ruling of the state's highest court.

Electoral College

The United States uses an "Electoral College" system rather than electing the president with a simple majority.

Based on their population, each state is worth a certain number of electoral votes, with 270 out of 538 total required to win. 

A majority of Texans, for example, will likely vote Republican, handing that candidate the state's 40 electoral votes. Meanwhile, the 28 electoral votes in Democratic stronghold New York will almost certainly go to Biden.

With many states already firmly leaning one way or the other, the election will hinge on winning key "swing states." 

This year, eyes are on Arizona, Georgia, Michigan, Nevada, Pennsylvania and Wisconsin.

'Calling' the results

Officially, the winner of the White House is not decided until every state has certified its vote count.

But the race is typically "called" by major news organizations on election night, based on their tabulations of reported totals, district by district.

They make a decision on the winner of each state, and finally the entire election, when it appears there is no mathematical way for one candidate to overcome his deficit and the other has a sure path to the magic number of 270 electors.

Ronald Reagan's 1980 landslide victory was called at 8:15 pm, whereas in 2000, the election came down to who won Florida. Divided by a few hundred votes, the two candidates battled in courts for weeks until the Supreme Court weighed in and halted recounts, handing the election to George W. Bush. 

The winner will be sworn in on Inauguration Day, January 20, 2025.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)