The American Civil Liberties Union of Ohio filed the challenge Monday in U.S. District Court to Cuyahoga County's move back to paper ballots away from electronic touch-screen systems, a release on the group's Web site stated.

The ACLU said other counties using electronic systems notify a voter if they make an error while the paper ballot system doesn't, which contravenes the U.S. Constitution's equal protection laws.

ACLU of Ohio Staff Attorney Carrie Davis, in a release, said: "Voting rights experts and Ohio's own elections officials agree that voters must be alerted to possible problems with their ballot. Hopefully, the court will prevent Cuyahoga County from implementing this dangerous technology in the March 2008 primary and protect voters from having their ballots left uncounted."

Cuyahoga County Prosecutor Bill Mason was critical of the ACLU challenge and through a spokesman called its timing "reckless and shortsighted," The Plain Dealer, a Cleveland newspaper, reported.

A hearing was set for Tuesday on the ACLU's request for an injunction, the report said.