President Obama's re-election campaign is suing Ohio's top elections official in a dispute over a state law that restricts early, in-person voting during the three days before Election Day. 

The lawsuit filed Tuesday in federal court in Columbus follows a series of election law changes cleared by the state's Republican-controlled Legislature and signed by its Republican governor, John Kasich. 

Obama's campaign and Democrats argue that the law unfairly ends early, in-person voting for most Ohioans on the Friday evening before the election but gives military personnel and overseas voters until Monday to cast ballots. 

Before the changes, local election boards could decide whether to allow in-person voting during those final three days. 

In 2008, about 30 percent of Ohio's total vote came in before Election Day.