The Supreme Court's conservative majority is skeptical of state laws that allow the counting of late-arriving mail ballots, a controversial issue for President Donald Trump. The court is hearing arguments in a case from Mississippi that could affect voters in 13 other states and the District of Columbia, potentially affecting an additional 15 states that have more forgiving deadlines for ballots from military and overseas voters. The challenge is part of Trump's broader attack on most mail balloting, which he believes breeds fraud. The ruling is expected by late June, early enough to govern voting in the 2026 mid-decade congressional elections. The issue before the court is whether federal law sets a single Election Day that requires ballots both cast by voters and received by state officials.