Conservative justices appeared ready to strike down so-called “grace periods” for election officials to count mail-in ballots after Election Day.

Signaling a threat to millions of voters who cast mail-in ballots across the country and overseas, the Supreme Court’s conservative majority appeared ready Monday to bless a recent push by Republicans to restrict how and when late-arriving mail-in ballots are counted.

The Republican National Committee, and Mississippi’s Republican and Libertarian parties have asked justices to unwind a Mississippi law passed in 2020 that allowed absentee voters to mail in their ballots with a postmark as late as Election Day. Under the state law, election officials were ordered to count ballots received as late as five days after Election Day. (Over 30 states currently have grace period rules for mail-in ballots that are similar.)

Paul Clement, the attorney representing the Republican National Committee, told the justices that all ballots, including mail-in ballots, must be received “into official custody” and counted by Election Day or be invalidated.

Seemingly suddenly disinterested in preserving states’ rights, Justices Neal Gorsuch, Clarence Thomas, Amy Coney Barrett and Brett Kavanaugh repeatedly appeared to share the RNC’s sentiments about the necessity of a singular Election Day —or one without grace periods for the counting of ballots. Justice Samuel Alito appeared to put a fine point on the majority’s grievances.