A new United States Postal Service (USPS) policy, called Regional Transportation Optimization (RTO), may lead to the rejection of tens of thousands of mail-in ballots in the November elections, according to a report from the Brookings Institution. The policy reduces the number of truck visits to rural post offices from two per day to one, which could slow down the processing and delivery of mail. This delay might cause some ballots to arrive after the deadline, making them ineligible to be counted. The report, written by Brookings senior fellow Elena Patel, estimates that the change could result in between 43,000 and 55,000 additional mail-in ballots being rejected nationwide. The impact is expected to be most severe in rural areas of the western United States, where post office service is already less frequent and where many states automatically send mail ballots to registered voters. These regions are particularly vulnerable because they rely heavily on the postal system for voting access. The RTO policy was introduced by the USPS in response to a sharp decline in letter volumes. Single-piece first-class mail has dropped from 57 billion pieces in 1997 to just 12 billion in 2023. Previously, each post office received two truck visits per day—one to deliver mail in the morning and another to collect it later. Now, post offices more than 50 miles from their regional plant will only have one pickup and drop-off per day. This change is separate from recent efforts by the Trump administration to restrict mail-in voting, which have faced legal challenges. While the Supreme Court has not intervened in some of these disputes, the administration continues to push for restrictions. Approximately 121 million of the country’s 253 million voting-age adults in the 48 contiguous states and Washington, D.C., live near a post office that will now have only one daily pickup. These post offices serve about 47% of all voting-age adults. Patel’s analysis focused on three states—California, North Carolina, and Washington—each of which held a primary election earlier this year. Her findings showed that the RTO policy could double the rate of mail-in ballot rejections in these states. In California and Washington, the overall rejection rate for mail-in ballots was around 1%, while in North Carolina, it was several times higher. Mail-in voting is increasingly common, with nearly one in three Americans voting by mail in the 2024 general election, totaling about 48 million votes. Around 40% of mail-in ballots in recent elections came from areas affected by the RTO policy. Patel recommends that voters send their ballots early to avoid delays, as the USPS has indicated that a postmark may no longer reliably show the date a ballot was sent. The Supreme Court has ruled that a postmark can be used as proof a voter met the deadline, but several states have eliminated grace periods that once allowed late-arriving ballots to be counted. Patel suggests that states and counties should clearly communicate the changes to voters affected by RTO, and the USPS should identify which post offices are now under the one-pickup policy to help voters understand the new constraints.