CHICAGO — A top adviser to President Barack Obama’s campaign lashed out at Mitt Romney on Sunday, arguing that the presumptive Republican nominee is misrepresenting a lawsuit Democrats filed in Ohio to equalize voting rights.

The suit, which Romney has seized upon to argue that Obama is trying to undermine service members’ voting rights, calls for all Ohioans to be able to cast early votes until the day before Election Day.

“What that lawsuit calls for is not to deprive the military of the right to vote in the final weekend of the campaign. Of course they should have that right. What that suit is about is whether the rest of Ohio should have the same right, and I think it’s shameful that Gov. Romney would hide behind our servicemen and women,” Obama campaign strategist David Axelrod said on “Fox News Sunday.”

Until 2011, all Ohioans could cast early ballots as late as the day before Election Day. Last year, the Legislature instituted a Friday cutoff for all voters except members of the military and their families.

In mid-July, the Obama campaign and Democratic groups sued, arguing a two-tier voting system was unconstitutional and calling for all voters to be allowed to cast ballots until the day before Election Day. The suit does not call for reducing early voting access for service members.

Romney accused Obama of trying to undermine service members’ voting rights. “President Obama’s lawsuit claiming it is unconstitutional for Ohio to allow servicemen and women extended early voting privileges during the state’s early voting period is an outrage,” Romney said in a statement Saturday.