Alabama says it plans to move ahead with a requirement for potential voters to show concrete proof of citizenship, in the first sign of a wider impact from a court decision on Wednesday ordering a federal elections agency to help Arizona and Kansas enforce their own such requirement.

Alabama is one of the four states that have adopted the extra layer of proof for people registering to vote. With such rules under a legal cloud, it held off on carrying them out. Now that may change.

The federal court decision “has given us the confidence that Alabama has strong footing for implementation of the rules regarding proof of citizenship,” Secretary of State Jim Bennett said in an email.

The ruling, by a district court in Wichita, Kan., is all but certain to be appealed, parties in the case said, and is unlikely to be the last word in decades-old fights over who gets to make the rules for voting and what they may require.