COLUMBUS (AP) — A free-market think tank has launched a billboard campaign advocating what it’s calling “worker voting rights” amid renewed efforts at the Statehouse to make Ohio a right-to-work state.

The Buckeye Institute says the outdoor advertising campaign in Columbus it announced Wednesday is meant to raise awareness among unionized public-sector workers who aren’t given a vote on what labor organization represents them.

Two conservative Republican lawmakers on Tuesday put forth a package of proposed constitutional amendments to limit unions. State Reps. John Becker and Craig Riedel (REE’-duhl) are aiming for the 2020 ballot.

That’s after Republican Gov. John Kasich leaves office.

Ohioans voted overwhelmingly in 2011 to repeal GOP-passed collective bargaining limits. Kasich said after the vote that he wouldn’t support future efforts to limit unions.