Over the chants of hundreds of union members opposing the bill, the committee passed a measure that would put the right to work issue on Minnesota's ballot in November. 23 states have enacted similar laws that make union membership voluntary, rather than compulsory.

Union members by the hundreds filed into the state Capitol on Monday morning as a group of Senate lawmakers discussed a proposed constitutional amendment that would make it harder for unions to organize. Critics of the bill say it would lower wages and cut benefits for middle-class families. Supporters say it would help businesses create new jobs.

The constitutional amendment would not allow contracts to require employees to join unions or pay dues. Sen. Dave Thompson of Lakeville continues to stress the measure will not impact collective bargaining in Minnesota.

Union members are coming by the busload to protest a constitutional amendment that would end a requirement that some workers belong to unions. Labor leaders say it would only mean fewer jobs and lower pay.

Republican Senator Dave Thompson of Lakeville is pushing a proposal that would allow Minnesota workers to opt out of unions. If lawmakers pass his "right to work" legislation, the question would appear before voters in the fall as a proposed amendment to the state Constitution.

Leaders in the AFL-CIO, which produced the ad that starts airing Tuesday, says the bill is "a power grab" meant to weaken collective bargaining. Union members worry it would ultimately lead to less compensation for middle-class families, but Republican legislators behind the bill say it would attract new business and create jobs.

Democrats complain the bill weakens wetland protections and the authority of the Pollution Control Agency. The bill's sponsor defends it, saying "it's not way over the top like it's accused of being."