(AP) – Voters in at least three states could get a chance to decide next year whether to limit the fees that unions can collect.

After recent successes in Michigan and Indiana, supporters of “right-to-work” laws now are focusing their efforts on Missouri, Ohio and Oregon. But instead of relying on potentially reluctant governors to enact the measures, they are looking to place the issue before voters.

Initiative petition campaigns are underway in Ohio and Oregon. In Missouri, the Republican-led Legislature will consider whether to refer the measure to the 2014 ballot.

Two dozen states currently have “right to work” laws that prohibit union fees from being a condition of employment.

Conservative lawmakers and business groups have been leading the charge. Unions have opposed the measures with mixed results.