WICHITA, Kan. –  A judge said Tuesday that Kansas can’t require people to show proof of U.S. citizenship when registering to vote for federal elections at motor vehicle offices.

U.S. District Judge Julie Robinson ruled that the state’s proof-of-citizenship requirements likely violate a provision in the National Voter Registration Act that requires only “minimal information” to determine a voter’s eligibility. She ordered Kansas to register thousands of voters whose paperwork is on hold because they did not comply with the requirement. But she put her preliminary injunction on hold until May 31 to give the state a chance to appeal.

The state immediately said it would appeal. Unless a higher court halts Robinson’s order before the end of the month, it would take effect then, clearing the way for those residents to cast a ballot in the upcoming federal elections.

Robinson wrote that “even if instances of noncitizens voting cause indirect voter disenfranchisement by diluting the votes of citizens, such instances pale in comparison to the number of qualified citizens who have been disenfranchised by this law.”