California Mail-in Ballot Rejection Causes and Concerns

Almost 150,000 mail-in ballots were rejected during California’s June primary election due to late arrival. This marks an increase from previous elections, despite reforms aimed at enhancing voter participation and counting every ballot. California is well known for its delayed vote counts, which can last for weeks. This delay often results from policy changes over time intended to boost turnout.

One notable change allows for mail-in ballots to be received up to seven days after the election day, as long as they are postmarked by Election Day. Despite this additional time, late-arriving ballots remain the main reason for higher rejection rates. According to data from the California Secretary of State, postmarks dated after Election Day contribute significantly to this issue. Experts suspect alterations in U.S. Postal Service procedures might affect when these postmarks are applied.

The June primary recorded 148,241 rejected mail ballots, a 1.73% rejection rate. This figure rose from 108,982 rejected mail ballots in the 2024 primary, which had a 1.56% rejection rate. In 2022, 105,818 ballots were voided at a similar rate. Late-arriving ballots accounted for 93,479 rejections, surpassing previous counts of around 70,000 in 2022 and 76,000 in 2024. This rise occurred despite fewer voters participating in those elections.

Kim Alexander, president of the nonpartisan California Voter Foundation, expressed concerns over the increase in rejections due to late postmarks. These delays may link not only to postal processes but also to a surge of last-minute voting in June’s wide-open governor race. “Ballots rejected due to lateness are primarily caused by being postmarked too late, not arriving too late,” Alexander emphasized.

Rejection rates vary over time, but the elevated numbers for lateness urge officials to examine the cause, explained Mindy Romero, director of the Center for Inclusive Democracy. Lawmakers raised alarms over potential delays from USPS changes in postmark timing, which might not reflect the actual date received. The centralization of processing centers is a factor that could extend postmarking delays.

Some Democratic U.S. senators, concerned about election year disruptions, highlighted these issues in a letter to USPS in January. The policy updates may indicate mail-handling dates from processing centers instead of initial receipt dates. Further concerns were raised by U.S. Sen. Tammy Baldwin and Gov. Tony Evers of Wisconsin after significant delays affected April’s election ballots.

In June, California election officials had already advised voters to send ballots early due to anticipated slower services. Tulare County registered the highest rejection rate at 3.52%, followed by Alpine County and Merced County, each at 3.36%.

Other rejection reasons included mismatched signatures and unsigned ballots. Approximately 44,000 ballots were set aside due to signature mismatches, and over 8,300 lacked signatures on the return envelope. A few hundred ballots were voided because they were already submitted by the voter or multiple ballots arrived in one envelope.

While vote-counting is swift in states like Florida and Texas, California’s process is notably slower. Former President Donald Trump criticized California’s election operations, reinforcing claims of inefficiency. However, a Brookings Institution report in 2025 highlighted the rarity of mail voting fraud, with only four cases per 10 million mail ballots, despite its growing popularity among both Democrats and Republicans.