WASHINGTON — Voters in more than a dozen states will cast their choice for U.S. president Tuesday in the largest single day of nominating contests on the 2024 election calendar.

President Joe Biden and former President Donald Trump, the clear Republican front-runner, are chasing more than one-third of their respective parties’ delegates during the “Super Tuesday” races.

Contests will be held in Alabama, Alaska, Arkansas, California, Colorado, Maine, Massachusetts, Minnesota, North Carolina, Oklahoma, Tennessee, Texas, Utah, Vermont and Virginia, and the U.S. territory of American Samoa. Iowa Democrats will also announce unofficial results from their mail-in caucus.

A unanimous U.S. Supreme Court decision Monday allowed Trump to remain on the primary ballot in Colorado, striking down an unprecedented decision by the state’s highest court to remove the former president. The Colorado court ruled Trump’s actions during the Jan. 6 attack on the U.S. Capitol disqualified him from contention under a Civil War-era constitutional clause barring insurrectionists from holding future office.

While the delegate math doesn’t add up for either Biden or Trump to clinch the Democratic or Republican nominations Tuesday night, the one-day wave of primaries and caucuses is expected to set up both men for presumptive-nominee status later this month.

Trump, who has won all but one primary contest so far, has picked up 273 delegates of the 1,215 needed to secure his party’s nomination, according to the Associated Press delegate tracker.

Former South Carolina Gov. and United Nations Ambassador Nikki Haley, Trump’s remaining GOP primary challenger, has gained 43 delegates, including all 19 of the party’s District of Columbia delegates over the weekend.

A total of 854 of 2,429 Republican delegates are up for grabs this Super Tuesday, with many states awarding their entire delegate totals to the candidate who reaches the majority of the vote.

California and Texas carry Tuesday’s two largest delegate counts at 169 and 150, respectively. Texas GOP rules state that another 11 delegates will be awarded at the party’s convention in May.

Biden has so far clinched 206 of 3,934 Democrat party delegates. A possible 1,420, more than one-third of the delegate count, are available in Tuesday’s races. Democrats award their delegates proportionally to candidates who receive at least 15% of each race’s vote.

Biden’s campaign has not faced a serious challenge, with only an “uncommitted” protest vote in Michigan’s late February primary gaining enough support to garner two delegates.

Biden’s Democratic primary challengers, author and activist Marianne Williamson and U.S. Rep. Dean Phillips of Minnesota, have yet to receive any delegates.

AP projects Trump could tie up his party’s presumptive nomination by March 12, and Biden as early as March 19.

Democrat and Republican primary voters will head to the polls in Georgia, Mississippi and Washington on March 12, as will GOP voters in Hawaii. Democrats in Hawaii will vote a week earlier on March 6.

Both parties will hold presidential primary contests in Arizona, Illinois, Kansas and Ohio on March 19. Republicans will also vote that day in Florida. The Sunshine State is no longer holding a Democratic primary.

Candidates with a majority of delegates are officially nominated at each party’s massive summer conventions. Republicans will meet July 15-18 in Milwaukee, after which Democrats will convene Aug. 19-22 in Chicago.

Barring any surprise circumstances, Biden and Trump are expected to receive their party’s nominations.