A major election question could soon land in front of the U.S. Supreme Court, with implications for how mail-in ballots are counted in states like California. Right now, California counts ballots postmarked by Election Day as long as they arrive within a week. The court is signaling interest in a case that challenges that practice, after a lower court said late-arriving ballots should be rejected. Election law experts say the court is likely to side with states’ rights to set their own rules, with a ruling expected later this summer.