Mail-in voting faces regulatory and delivery challenges in US

Mail-in voting practices and ballot delivery reliability are facing scrutiny ahead of upcoming elections. In Arizona, the U.S. Supreme Court has blocked the Trump administration from implementing new rules for mail-in voting, though the practice may face future restrictions.

In California, a study by the Public Policy Institute of California indicates an increasing trend of mail-in ballots being rejected for arriving late. The study found that 1.1% of mail ballots in the June 2026 statewide primary arrived after the deadline, up from 0.3% in 2024. Researchers attributed this rise to changes in U.S. Postal Service operations, specifically the elimination of certain evening mail pickups, which can delay postmarking. Similar increases in late ballot rejections were noted in Washington and Oregon.