George Richardson mailed in his ballot to vote in Texas in 2018, but after Election Day officials in Brazos County told him it wasn’t counted. When Richardson asked why, the told him they concluded the signature on his ballot wasn’t really his, according to a lawsuit filed in federal court in Texas on Wednesday.

Something similar happened to Rosalie Weisfeld. She’s voted regularly over the last 30 years, and did so with an absentee ballot in the 2019 election in McAllen, Texas, because she was going to be out of town on Election Day. She was only told afterward that her ballot wasn’t counted ― officials said they determined her signature didn’t match one they had on file.

Richardson and Weisfeld were among at least 1,800 Texans who had their ballots rejected because of signature issues, according to the suit. The two ― along with multiple disability and advocacy groups ― are parties in the suit, arguing that the Texas process for disqualifying ballots over the signature issue violates the U.S. Constitution’s guarantee of equal protection of law and due process, as well as the Americans with Disabilities Act and the Rehabilitation Act of 1973.

As part of their review of mail-in ballots, local election officials can set up a committee to review the signatures on them. The committee members, in turn, compare the signature on a mail-in ballot with the one on the ballot application to try to ensure it came from the same person. These officials also can compare the signature on the ballot with at least two signatures on file from the prior six years.

If the ballot is rejected, local officials don’t have to notify the voter until 10 days after Election Day that their vote wasn’t counted.

In their complaint, lawyers for the plaintiffs noted that the Texas election code outlines no process those officials, who aren’t handwriting experts, are supposed to follow in comparing signatures.

The state relies “on untrained officials to ‘eye-ball’ a signature, leaving the sacred right to vote up to chance,” said Hani Mirza, a lawyer with the Texas Civil Rights Project who is helping represent the plaintiffs. “It’s time that we modernize this process and ensure that not one single Texan has their ballot thrown out for arbitrary reasons.”

The suit says Texas is violating the Constitution’s 14th Amendment, which guarantees equal protection under the law, by not implementing a uniform, statewide standard for verifying the signatures. It also contends that voters are being denied the 14th Amendment’s guarantee of due process because they do not have a chance to verify their signatures before a ballot is rejected.

The signature verification process violates the Americans with Disabilities Act and the 1973 Rehabilitation Act, the suit argues, because voters with disabilities may not be able to make previous signatures match.

Using a mail-in ballot in Texas is restricted. Only people who are at least 65 years old, or are out of their county during early voting periods and on Election Day, or have a disability, or are in jail but eligible to vote can use such ballots.

The plaintiffs want a federal judge to either block officials from rejecting a mail-in ballot because signatures are ruled not to match or to require the officials to give voters a chance to fix their ballots before the votes are rejected.

Last year, a federal judge in New Hampshire blocked a similar process there, ruling that “the absence of functional standards is problematic.”

In Florida, a measure signed into law this year establishes processes for comparing mismatched signatures and giving voters extra time to “cure” ballots in question. The fix came after a federal judge, in the wake of the 2018 election, ordered the state to give voters more time to validate questionable ballots.

CORRECTION: An earlier version of this article incorrectly stated the year Weisfeld’s mail-in ballot was rejected. It was 2019, not 2018.