A top appeals court has overturned a federal official’s ruling that effectively allowed three states to insist on proof of citizenship when their residents try to register to vote.

The official, U.S. Election Assistance Commission executive director Brian Newby, agreed in January to change a national mail-in voter registration form to allow Alabama, Georgia, and Kansas to implement state laws requiring proof of citizenship.

Several voting rights groups, including the Brennan Center, the Lawyers’ Committee for Civil Rights Under Law, and the American Civil Liberties Union, asked for a temporary restraining order in February to stop Newby’s decision from going into force, arguing that the new requirements would sow confusion and make it harder for some people to register – and therefore make it more difficult for the groups to carry out their mission.

But U.S. District Court Judge Richard Leon declined their request, contending that the registration deadlines for the states’ primary contests had already passed and that the plaintiffs hadn’t shown they would suffer “irreparable harm.” He affirmed that decision after a court hearing in March, and the advocacy groups appealed in July.

“Appellants have demonstrated irreparable harm, a likelihood of success on the merits, that the balance of equities tips in their favor, and that an injunction is in the public interest,” the U.S. Circuit Court of Appeals for the D.C. Circuit ruled late Friday, ordering the three states to disregard Newby’s instructions.

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