Mail-in ballots are being rejected at a growing rate in rural areas thanks to U.S. Postal Service cuts.

ProPublica reports that in the primaries this year in Oregon, North Carolina, Washington, California, and Ohio, a staggering amount of ballots arrived too late to be counted due to delays in mail delivery. Three days after primary elections in Stevens County, Washington, election workers checked the mail for late ballots. They found over 500 envelopes when they were only expecting a few dozen.

The same thing happened in all of eastern Washington’s 11 rural counties. Over 2,000 ballots came in late, compared to just 600 late ballots in 2022’s midterm elections. The nonprofit news outlet traces the issues to a number of changes at the USPS.

First, over the past three years, the postal service moved to process first-class mail at regional hubs instead of smaller plants closer to local post offices. Then, just after the presidential election two years ago, the USPS cut in half its pickups from post offices at least 50 miles away from those hubs.

That increased delivery time by at least one day. Postmarks, which are critical for legally verifying if a ballot can be counted, were also pushed back as those stamps aren’t added until mail reaches a regional processing center.

In rural counties in the five states, late ballots have a grace period as long as they are postmarked by Election Day, but rejections still shot up compared to 2022 according to ProPublica’s findings.

The postal service’s policy changes were pushed by Trump administration officials, and likely unintentionally hurt the Republican Party.

“I don’t think they realized how much it was going to affect their voter base,” Washington Secretary of State Steve Hobbs, a Democrat, told ProPublica, noting that his state has “a lot of rural Republican voters.”

USPS officials claim that delays are much less likely for November’s general election because of “extraordinary measures.” The postal service sent a memo to every post office in the country earlier this fall instructing them to separate ballots from other mail for the 10 days preceding Election Day on November 3. The memo said that the post offices should deliver the ballots on the day they arrive.

“We work to identify and address issues quickly,” said the chair of the Postal Service board of governors Amber McReynolds in a press conference last week, “so ballots can continue to move swiftly from election offices to voters and from voters back to election offices.”

If they are wrong, though, many races could be affected. A few thousand or even hundred ballots could swing many contests in rural areas, leaving voters across the political spectrum disenfranchised. Trump’s attempts to undermine the entire process aren’t helping, either.