A cost-cutting change to how the Postal Service handles outgoing mail at post offices is quietly undermining the vote-by-mail process. In states that rely on Election Day postmarks, a growing share of ballots are being rejected — not for arriving late, but for lacking a timely postmark.

Earlier this week, a special election was held in Washington state, with counties voting on school budgets, bond issues, and other local measures. In advance of the election, state officials urged voters to use ballot drop boxes rather than the U.S. mail. They warned that recent changes at the Postal Service put ballots at risk of being rejected due to late postmarks.

But if the Court doesn’t announce a decision before the November midterms, or if it decides to permit states to continue using the postmark deadline, the Postal Service’s change in postmarking practices could end up disenfranchising thousands of voters and have a significant effect on the outcome of close races.

The RTO’s impact on postmarks

Traditionally, mail is collected at the end of the day and transported to processing centers, where letters are scanned and postmarked, almost always on the same day they were sent. 

This same-day postmark is the foundation for the mailbox rule aka the posting rule, a legal concept used in tax law, contracts, and elections where “timely mailing is treated as timely filing.” In the context of U.S. tax law, the concept is codified in 26 U.S. Code § 7502.

In 2024, the Postal Service began an initiative called Regional Transportation Optimization (RTO). Under RTO, the mail is no longer collected at the end of the business day. Letters are instead bagged and held at the post office until the following morning, when they’re collected at the same time the day’s mail is dropped off for delivery. By combining delivery and collection into a single trip, the Postal Service cuts its costs

However, this change in the transportation system means that letters which would have otherwise been postmarked the day they were sent are instead postmarked a day later. A voter might deposit a ballot on Election Day, but the postmark will show the following day, leading to a disqualified ballot. 

Even a ballot mailed on the Monday before Election Day — if it’s deposited after the final bagging of the mail for a Tuesday morning pickup — may not be postmarked until Wednesday — too late to be counted as valid.

The RTO applies only to post offices more than 50 miles from one of the country’s 56 Regional Processing & Distribution Center (RPDCs). Post offices outside this radius are subject to RTO.

The plan has been implemented region by region for the past two years. When it’s fully implemented, the RTO will affect about 24,000 of the 31,000 post offices nationwide. As of April 1, 2026, the plan had been activated at about 14,300 post offices.

At this point, the plan has impacted about 88 million people nationwide. Eventually, the RTO will encompass 156 million people — nearly half the country’s population.

You can check the RTO status of any location using the RTO Status Checker in the sidebar on this page. Type in a ZIP Code or a place name and state, and hit enter. The Checker will indicate if a location has already been activated for RTO,  if it’s eligible for RTO but not yet activated, or if it’s exempt from RTO because it’s within 50 miles of a RPDC.

RTO implementation in Washington

In Washington, about 330 of the state’s 520 post offices have lost the evening collection under the RTO. About one-third of the state’s population live in RTO-impacted ZIP Codes.

Washington is served by three RPDCs — in Seattle, Spokane, and Portland. Post offices within 50 miles of these RPDCs are not affected by RTO, and ballots sent at these offices will presumably continue to get a same-day postmark.

In Washington, the RTO was activated in three phases. The first phase took place in February 2024 as part of the RTO pilot, Local Transportation Optimization (LTO). This activation impacted areas in the southwestern part of the state (ZIP prefix 986), which are served by the RPDC in Portland. 

The second phase, implemented in August 2025, covered the eastern half of the state (ZIPs 988-991 and 993-994). The third phase, implemented on November 15, 2025 (a week after the special election), impacted the northwestern part of the state (ZIPs 980-983, 985).

Here’s a map showing the phases of RTO implementations. The yellow areas indicate the ZIP codes within 50 miles of one of the three RPDCs. The green shows phase one, the light blue, phase two, and the dark blue, phase three. Scroll over the map for details.

The 2024 election would have been impacted only by the phase one RTO activations. The election in November 2025 would have been impacted by both phase one and phase two. By the date of the special election in February 2026, the RTO was implemented throughout the state.

Washington elections 2022-2026

Washington uses an all-mail election in which ballots are sent to all registered voters. About two-thirds of the ballots are returned via drop boxes, usually located near city hall, schools, and election centers, while about a third of the ballots are returned through the Postal Service. In 2026, over 44 percent of the votes were sent through the Postal Service.

In this discussion, “mail ballots” refers to those returned by postal mail, not drop boxes.

Here’s a table showing election results in Washington for the 2022 midterms, the 2024 presidential election, and two special elections in 2025 and 2026.

Late postmarks represent a growing portion of rejected ballots. In 2022, they accounted for 22 percent of rejected ballots. By 2026, that figure skyrocketed to 73 percent. Here are a couple of charts showing reasons for rejection in 2022 and 2026.

Reasons for Ballot Rejections in 2022 and 2026

In 2022, the statewide late postmark rejection rate as a percentage of mail ballots was 0.69%, representing 8,358 rejections out of approximately 1.21 million mail ballots. In 2024, the rejection rate due to late postmarks declined somewhat, as is typical in presidential elections (as discussed below). In 2024, there were 4,600 late postmark rejections,  0.34 percent of mail ballots.

The situation shifted radically in the special elections in 2025 and 2026. In 2025, the rejection rate due to late postmarks surged to 2.09 percent of mail ballots (14,741 rejections out of 705,984 ballots), and in the February 2026 special election, the rate reached 3 percent, with 10,486 rejections out of a much smaller pool of 350,670 mail ballots. 

If the rejection rate in the upcoming midterms reaches the 2026 level of 3 percent and the number of mail ballots is similar to the 2022 level of 1.2 million, it would mean about 36,000 ballots could be rejected due to late postmarks — more than four times as many rejections as in 2022.

Rejections in off-year elections

As the table above shows, the rejection rate in 2024 was lower than in the off-year elections, and the two special elections have notably higher rates. This a common phenomenon for which there are several explanations, as discussed in this report on ballot rejections in Washington State 2020-2024.

Off-year elections tend to attract a higher proportion of infrequent or first-time voters who are less familiar with the specific “must be postmarked by Election Day” rule. These elections also have a relatively low profile, so some voters may not realize it’s Election Day until the last minute, so they rush to the post office and miss the deadline.

In addition, high-profile presidential campaigns invest heavily in “ballot curing” outreach, helping voters fix mistakes before they lead to final rejections. In off-years, this support network is largely absent.

While voter behavior thus accounts for some historical variation, the sharp spike in late-postmark rates in 2025 and 2026 is almost certainly due to changes in Postal Service postmark practices.

Election impacts of RTO

To get a clearer sense of the extent to which late postmarks as opposed to voter behavior are causing ballot rejections, one can contrast areas where RTO has been implemented with areas that are excluded from RTO because they’re near an RPDC.

The Postal Service is implementing the RTO in ZIP Codes where the post office is more that 50 miles from a RPDC. Washington reports election data by county, and some counties include both RTO and not-RTO ZIP Codes. For purposes of this analysis, the counties with a relatively low percentage of the population subject to RTO are considered “not RTO” counties. For the Seattle RPDC, this includes King, Pierce, and Thurston counites. The Spokane RPDC area includes Spokane and Lincoln (two-thirds of its population are not-RTO) The Portland RPDC area includes Clark, Cowlitz and Skamania.

Here’s a table showing the mail ballots and postmark rejection rates for the four elections comparing counties where RTO was implemented with those where RTO was not implemented.

Here’s a chart, based on that data table.

In the counties not impacted by RTO, the late-ballot rejection rate increased from 0.72 percent in 2022 to 1.43 percent in 2026. This increase would have had nothing to do with RTO. It’s primarily due to voter behavior. 

The rejection rate for the RTO counties, on the other hand, increased from 0.67 percent in 2022 (similar to the not-RTO rate) to 4.64 percent in 2026. Some of this dramatic seven-fold increase was caused by voter behavior, but most of it was due to the RTO.

Counting by county

These numbers represent the aggregate totals for RTO and not-RTO counties. The following table drills down to the county-level and compares the 2022 midterms and the 2026 special election (at which point the RTO had been implemented throughout the entire state).  The counties with an activation date of N/A are those within 50 miles of a RPDC and therefore not-RTO.

In some cases the county data samples are too small to be useful. But consider Snohomish County, where in 2022 about 900 ballots were rejected for a late postmark out of 118,727 mail ballots, a rejection rate of 0.76 percent. In 2026, 3,709 ballots were rejected out of only 57,155 — a rejection rate of 6.49 percent.

Franklin County saw a similar increase — from 0.77 percent in 2022 to 5.25 percent in 2026. In Yakima County, the rejection rate went from 0.59 percent in 2022 to 4.19 percent in 2026. These seven- and eight-fold increases in rejection rates for RTO counties may be contrasted with the non-RTO counties, where there were much more modest increases. Spokane went from 0.39 percent to 0.64 percent. King increased from 0.77 percent to 1.47 percent.

Here’s a map showing the rejection rates in 2026.

District by district

The impacts of RTO are not evenly distributed across the state’s ten Congressional Districts. In some, like the 7th, 9th and 10th, the percent of the population that’s subject to RTO is very small, while the 4th District is entirely subject to RTO.

Here’s a table showing the percentage of the population in each district subject to RTO. The column for RTO TBA is for ZIP Code areas that are eligible for RTO — they’re more than 50 miles from a RPDC — but that have not yet been activated for RTO, for one reason or another. It’s possible that that the plan has been tweaked somewhat and they will not be RTOed.

Here’s a map showing the districts, color-coded by the percent of the population subject to RTO. The darker the shade of blue, the greater the percent of the population subject to RTO.

Generally speaking, the districts with a high RTO percentage are more rural — and more Republican-leaning — than those with a low RTO percentage, which tend to be urban and to vote Democratic. In the districts where the RTO percentage is in the mid-range, the RTO voters tend to live in the rural areas of the district while the non-RTO voters live in the metropolitan areas around Spokane, Seattle, and Portland.

Most of the state’s districts have a history of going strongly for one party or the other, so it’s likely that RTO impacts, even if they surge in 2026, will not affect the outcome of any race. But there’s at least one notable exception.

According to Cook’s Political Report, the 3rd District, which encompasses southwest Washington, is a competitive “purple” district. In 2024, the 3rd voted for Trump for president while electing a Democrat to the House (with a margin of 16,123 votes). It’s the kind of district in other parts of the country where disqualified ballots could make a difference.

Alerting the public

The Postal Service has been sharing information about its postmarking practices with election officials, a Federal Register notice, and postings on its website. The Postal Service is telling voters to request a hand-stamped postmark at the counter in the post office to ensure their ballot is dated correctly.

But this assumes that voters will know about the postmark problem. They can’t be blamed if they don’t get the message. There are no signs at RTO post offices alerting customers that their mail won’t be collected and postmarked until the next day. Many voters are unaware that their long-standing habits may now lead to their votes being discarded. 

State election offials are urging voters to use drop boxes instead of the Postal Service, but in some rural areas, the post office may be more convenient, and it may be a matter of habit to use the postal system. It’s voting-by-mail, after all.

In the November midterms, there may be dozens of toss-up districts, as well as a few close Senate races. Some will involve states where there’s a significant number of mail ballots.

If the Supreme Court does not intervene via Watson v. Republican National Committee — which could potentially eliminate the postmark grace period entirely — these “arcane” postal changes may decide the outcome of the nation’s closest races.

The Washington State election data can be found on the Secretary of State’s website. There’s a thorough annual report on the 2025 election in Washington here. The data used for this post can be found on Google Docs here. You can check the RTO status of any ZIP Code or location on the RTO Status Checker in the sidebar of this website. There’s more about the postmarking issue here, and more about the RTO on our RTO dashboard.

— Steve Hutkins