CARSON CITY, Nev. (AP) - An initiative that would require secret ballot voting in union membership drives in Nevada has been filed with the secretary of state's office.

The "Save Our Secret Ballot" initiative is backed by business groups in at least 13 states as a response to a bill pending in Congress that would make it easier for workers to form unions by allowing them to sign authorization cards. Current practice allows employers to mandate secret ballot elections.

To qualify for the November 2010 general election ballot, organizers will need to gather 97,002 signatures. It would have to be passed by voters next year and again in 2012 to amend the state constitution.