Montgomery County election officials are worried that some mail-in ballots won’t be counted if the U.S. Postal Service changes the way it handles postmarks.

The county elections board on Wednesday released a letter it sent to USPS expressing concerns that the change could cause “serious issues” and penalize voters who did nothing wrong.

“We always strive to accept any timely ballots and reject only those that were untimely,” the letter said. “Postmarks ... have traditionally played a crucial role in that determination.”

State law requires that a ballot must be postmarked by or before the day of an election to be counted.

According to the USPS proposal, the rule change would make it so a letter’s postmark would not necessarily be the date on which the postal service first accepted a piece of mail, as is now the case.

A postmark under the new rule would indicate that USPS had a piece of mail in its possession on that date — but it would not be clear whether the mail arrived at USPS earlier.

In the language of USPS, the postmark would not “necessarily align with the date on which the Postal Service first accepted possession of a mail piece.”

Board President David Naimon said Monday that it is important for as many eligible ballots to be counted as possible, especially in local races where margins can be thin. He pointed to the 2022 Democratic primary for county executive, in which County Executive Marc Elrich won by just 32 votes over challenger David Blair.

“We’ve had close races,” Naimon said. “A small number of ballots that are invalidated, that should be valid, can swing a result.”

About 166,000 Montgomery County voters cast ballots by mail in the 2024 Presidential Election, according to the elections board. Under current state law, the elections board is not allowed to certify the results until 10 a.m. on the second Friday after the election. That is the deadline for receiving ballots.

Every election, the board has to reject hundreds of ballots received after the election certification deadline, even though they were postmarked on time, according to Naimon. Usually these straggling ballots were lost in the mail, he said. That’s bad enough, he said. But if the rule change goes through, he continued, ballots received after an election but prior to the certification deadline may have to be rejected as well.

Naimon said that while the rule may make sense for general mail, the board is hoping that the USPS will consider an exception for mail-in ballots. The decision to write to USPS was made unanimously by the seven-member board, which includes Democrats and Republicans.

“From our perspective, the ideal piece of mail would be postmarked on the date the USPS first takes possession of the mail piece from wherever it was mailed,” the letter read. “and additional postal markings would either be avoided or be sufficiently different from the original postmark so that election officials could piece together when the mail piece was originally mailed,” the letter said.

The county board is not the only group to voice concerns to the USPS. The Center for Election Confidence (CEC), a nonprofit focused on ethics in elections, also submitted a letter opposing the proposed rule change.

“Postmarks have been relied upon by governments, courts, litigants, and all manner of third parties to best discern the date and location of mailing for over 350 years,” CEC said in its letter. “Now after centuries of postmarks, the USPS’s Proposed Rule seeks to abdicate this responsibility.”

The USPS posted the proposed rule change in the Federal Register last month. Though there is no set date for passage of the rule, comments had to be submitted by Sept. 11, according to the register.