The U.S. Supreme Court on Wednesday heard oral arguments in a lawsuit led by U.S. Rep. Mike Bost (R-Illinois), challenging the Illinois mail-in voting law.

Bost and two Illinois primary delegates for President Trump sued the Illinois State Board of Elections in 2022, arguing against the state's law that allows mail-in ballots to be counted up to two weeks after the election as long as they are postmarked by Election Day.

Bost argues the policy violates federal law establishing an Election Day.

Both a lower federal trial court and a federal appeals court ruled Bost lacked standing to sue.

If the U.S. Supreme Court rules in Bost's favor, it could force lower courts to issue a ruling on the Illinois mail-in ballot law.