A federal appeals court has ruled in favor of a Texas law requiring voters to include identification numbers on mail-in ballots, overturning a lower court’s decision that had blocked the measure.

In a unanimous decision, a three-judge panel of the US Court of Appeals for the 5th Circuit upheld the 2021 law, determining it did not violate the Civil Rights Act of 1964. Federal law prohibits states from imposing voting requirements that are “not material” to determining voter eligibility.

“The number-matching requirements are obviously designed to confirm that every mail-in voter is indeed who he claims he is. And that is plainly material to determining whether an individual is qualified to vote,” Judge James Ho wrote in the ruling.

He added that relying solely on a voter’s name and address would be inadequate for election security.

“That information is easily available to anyone who simply requests it,” Ho said. “As a result, any person can request and receive that information about a registered voter, use that information to apply for a mail-in ballot, and then cast the ballot, with minimal risk of detection.”

Texas allows mail-in voting only under certain conditions, such as for elderly or disabled voters. The law mandates that voters include either a state-issued ID number or the last four digits of their Social Security number on both their mail-in ballot application and return envelope. Ballots that do not meet the requirement are rejected.

The Biden administration had filed a lawsuit challenging the law after it was enacted. Initially, a district judge blocked the law from taking effect. That ruling, however, has now been overturned, and the law’s enforcement is allowed to proceed.

“The 2021 Act easily complies with the materiality provision in any event,” Ho wrote.