The Supreme Court on Monday appeared poised to reject Mississippi’s mail-in ballot law, a decision that could upend mail-in voting throughout the country.

The Supreme Court on Monday is hearing a case that has become part of a broad political battle over mail-in ballots and that could have major consequences for voters in November’s midterm elections.

If the court strikes down the grace periods, it’ll leave some states and their voters scrambling to adjust with only a few months before absentee ballots are sent out this fall.