A panel of the 6th U.S. Court of Appeals in Cincinnati ruled Friday in a case targeting a state law that ends early voting for most residents on the Friday evening before a Tuesday election.
The law exempts military personnel and Ohio voters living overseas.
President Barack Obama's campaign and Democrats sued the state's elections chief and attorney general over the legality of the law. They argued that everyone should have a chance to vote on those days.
The state contended that many laws grant special voting accommodations for military members, and officials need time to prepare for elections.