New USPS Mailbox Rule Will Hinder Mail-in Voting

My mother and I have a ton of nerdy inside jokes that stem from my time in law school. They usually involve me making a huge mistake, then telling her about it, and her laughing because she made the same mistake in law school, or because it was such a silly error that hindsight made the blunder hysterical. For as long as I can remember, my mom would shout “Mailbox Rule!” whenever she mailed an important letter or document through one of those big, blue post office boxes.

You rarely learn a legal rule that is so simple and so exact that you can employ it in most cases without question and with complete confidence. In the Vanderpool family, we take great pride in celebrating the more straightforward legal rules at play, as if we had a superpower and were wielding it for good.

The mailbox rule, also called the “posting rule,” is the default rule for determining when acceptance of an offer forms a contract. Under the mailbox rule, an offer is legally considered accepted the moment the offeree mails a document, rather than when the offeror receives that document in the mail. This rule is based on the premise that a person who mails a letter hands it to a USPS employee, who then stamps it with a postmark that denotes the current date, thus sealing in that date for the record.

The Trump administration has now found a way around that legal rule to issue a new rule that creates doubt about whether ballots mailed in by voters on Election Day will receive postmarks on that same day, allowing them to be counted. This USPS formally announces a new rule on Dec. 24, when the fewest people possible would be paying attention. The post office, which is controlled by a board of governors composed of Trump acolytes, has now determined that a postmark may not be issued on the same day the post office takes possession of the mail.

The USPS claims to be clarifying an ongoing rule rather than officially changing the existing postmark, but this open acknowledgement that mail-in ballots will be overlooked at the discretion of the postal service is concerning as a lawyer and as a voter. The new rule holds implications for 14 states and Washington, DC, states that count ballots arriving after Election Day if they are postmarked on or before that day under a “ballot grace period.”

In these states, ballots mailed by voters before the deadline may not be counted if the postal service applies a postmark after Election Day. The USPS rule states that “the postmark date does not necessarily indicate the first day that the Postal Service had possession of the mail.” This new rule allows USPS stations in various locations where an election race might be closer to external officials to determine precisely when mail-in ballots will be counted and when they will be purposely held so they are not stamped after the deadline.

Mail-in voting surged in the 2020 General Election due to the COVID-19 pandemic, with 43% of voters casting ballots by mail. The percentage of voters mailing their ballots has fallen since that initial time, but it remains above pre-pandemic levels, given the convenience and ease of the mail-in method. According to data gathered by the US Election Assistance Commission, about 30% of voters still cast mail-in ballots in 2024.

While a vast majority of mail ballots were successfully cast last year, hundreds of thousands of ballots weren’t counted. During the 2024 election, 584,463 mail ballots sent in by voters were rejected by election officials, representing 1.2% of the total returned mail ballots. About 18% of the rejected votes were thrown out under the claim that they were not received before the deadline.

While 18% of that small percentage might not seem like a lot of rejected votes, when you consider how close some races will be in some regions, the ability of the now-partisan USPS to handpick the areas where they will delay a postmark to ensure the ballot does not count is extremely dangerous. This latest rule also comes as the US Supreme Court is preparing to consider a case late this spring or summer that could eliminate ballot grace periods nationwide, with a ruling issued right before the 2026 Midterm Elections.

While a decision by the Court could solve the issues created by this latest modification of the postmark rule, this newest rule could also be seen as a way for Trump to bolster his ongoing plan to deny mail-in votes in swing areas that will bolster the Republican Party’s chances of a win in 2026. If the Supreme Court does not explicitly address this issue in its ruling in a few months, Trump will be subject to the default rule now created by his USPS.

Officials at the USPS attempted to defend the covert change in a lengthy response to criticisms published in the Federal Register, emphasizing that the postal service is not responsible for administering elections and therefore does not advocate how citizens vote. But Trump’s extensive influence over how the mail is legally “received” and, thus, how ballots are counted under this new policy is undeniable.

As the postal service continues to shirk responsibility for these new changes publicly, one thing has become incredibly clear — anyone who is voting by mail before the next 2026 Midterm Election, who is at all close to the ballot deadline, needs to take their ballot into a post office now and request that it be hand-stamped with the date to preserve their vote. The mailbox rule, that everyone, including legal professionals, has long since come to rely on, needs to be amended to “the make sure you see someone hand-stamp your ballot with the correct pre-election date” rule.

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Amee Vanderpool writes the SHERO Newsletter, is an attorney, published author, contributor to newspapers and magazines, and an analyst for BBC radio. She can be reached at avanderpool@gmail.com or follow her on Twitter @girlsreallyrule.

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