BELLE PLAINE, Kan. (AP) — A former high-ranking election official violated federal law in 2016 when he granted requests by Kansas, Georgia and Alabama to modify the national voter registration form to require documentary proof of citizenship in those states, a federal judge ruled.

U.S. District Judge Richard Leon threw out the contested decisions made by Brian Newby, then-executive director of the Election Assistance Commission, an independent federal agency, after finding on Thursday that Newby failed to determine whether the proposed requirements were necessary to register to vote.

The long-...