President Obama’s reelection campaign filed a federal lawsuit against Ohio’s top elections official Tuesday in a dispute over the battleground state’s law that restricts in-person early voting in the three days leading up to Election Day.

The lawsuit, filed in Columbus, follows a series of election-law changes that were passed by the state’s Republican-controlled legislature and signed by Gov. John Kasich (R).

Obama’s campaign and other Democrats argue that the law unfairly ends in-person early voting for most Ohioans on the Friday evening before the Tuesday election while allowing military and overseas voters to cast ballots in person until Monday.

Before the changes to the law, local election boards had the discretion to set their own hours for such voting on the days before the election. And in-person voting on the weekend varied among the state’s 88 counties.

The state’s elections chief, Secretary of State Jon Husted, has argued that all counties should have the same early-voting hours and be open on the same days. Husted and his fellow Republicans contend it is unfair that a voter in one county can cast an early ballot on a day when a voter in a neighboring county cannot.

Obama for America was joined in the lawsuit by the Democratic National Committee and the Ohio Democratic Party.

Ohio is one of 32 states that allow voters to cast early ballots by mail or in person without an excuse. About 30 percent of the total vote in swing states — or roughly 1.7 million ballots — came in ahead of Election Day in the last presidential election.

Obama won Ohio in 2008, but Republican challenger Mitt Romney is expected to make a strong play for it in November.