The U.S. Supreme Court is hearing arguments on Monday to decide whether states can continue to count late-arriving mail ballots — an election issue targeted by President Donald Trump.

All 50 states require ballots to be cast or postmarked on or before Election Day, but 14 states have grace periods for receiving and counting regular mailed ballots, ranging from a day to several weeks after the election.

A final ruling will almost certainly come by late June, early enough to govern the counting of ballots in the 2026 midterm congressional elections.

Here's the latest:

Mississippi is among 14 states, along with the District of Columbia and three U.S. territories, with a grace period allowing late-arriving regular mail ballots to be counted after Election Day.

That ranges from a single day after the election in Texas to 21 days afterward in Washington state.

A total of 29 states allow extra time for at least some mail voters, including those who cast military and overseas ballots, according to the National Conference of State Legislatures and Voting Rights Lab.

Ohio, Kansas, North Dakota and Utah eliminated grace periods on their own last year, while Minnesota shortened its ballot deadline by a few hours.

Jesse Salinas, president of the California Association of Clerks and Election Officials, says his organization’s members are concerned that a potential ban on mail ballot grace periods could mean ballots of all kinds would be required to be counted by 11:59 p.m. on Election Day.

Large numbers of young voters use California’s same-day registration system to cast ballots that are typically counted after other tallies are completed.

“So all of those folks who will want to register and vote on Election Day, we just simply won’t have the ability to process all those” ballots before midnight, he said.

Alaska, more than twice the size of Texas, is dotted with small communities in far-flung places, many of them accessible only by air or water. Some political leaders and Native voting rights activists say the state’s 10-day grace period for absentee mail ballots is essential given the state’s unique geography and the limited postal service in rural areas.

In the 2022 general election, about 20% of all absentee ballots statewide were received after Election Day. The percentage was much higher for ballots from some of the state’s most rural communities.

The state’s senior U.S. senator, Republican Lisa Murkowski, says “there’s probably no other state where this ruling could have a more detrimental impact than ours.”

Alaska Native voting rights advocates and the state’s attorney general and solicitor general filed briefs with the Supreme Court to explain the importance of the state’s ballot grace period and the rationale behind it.