California rejected nearly 150,000 mail ballots in June primary

Nearly 150,000 mail ballots were rejected in California’s June primary. The most common rejection causes in mail voting are missing signatures, signatures that do not match voter records, ballots that arrive after the deadline, and envelope or paperwork defects.

California has built reporting and notice rules around that problem. The Secretary of State requires county election officials to report the number of rejected vote-by-mail ballots, broken out by reason, within 31 days of every election. Voters also have a right to be notified if a vote-by-mail or provisional ballot envelope is missing a signature or if the signature does not match the one on file, and counties may contact them by mail, telephone, email or through the state’s BallotTrax program.

In August 2017, the ACLU of Northern California, the ACLU of Southern California and Cooley LLP sued California over its voter signature-matching law. Tens of thousands of vote-by-mail ballots had been invalidated by mismatch procedures. A Stanford Law School policy practicum report published May 15, 2020 examined California’s signature verification rules under the Every Vote Counts Act.

Assembly Bill 3184, introduced by Assemblymember Marc Berman on Feb. 16, 2024 and heard April 24, 2024 by the California Assembly Committee on Elections, would have changed how the Secretary of State reports ballot-rejection data, limiting some reporting to elections for state office. On March 18, 2025, Kim Alexander, president of the California Voter Foundation, testified before the Senate Standing Committee on Elections and Constitutional Amendments about California’s signature curing process.

U.S. Postal Service changes affected when postmarks were applied. California ballots must be returned on time, and cure notices only help if counties can reach voters before the ballot is discarded.