The measure, termed by supporters as "right to work," would keep employers from forcing their workers to join a union or pay union dues or fees as a condition of employment, either before or after hiring.
The Senate gallery was full of union worker protesters who coughed or cackled in objection throughout the bill's debate and earning the loud reprimand of the president pro tem's gavel.
The bill's sponsor, Sen. Luann Ridgeway, R-Smithville, said the measure would bring in more jobs to the state and make Missouri more competitive with neighboring states. All of Missouri's neighboring states, with the exception of Illinois and Kentucky, have ended collective bargaining and then gained jobs, she said.
"We can not continue to go down this path where our citizens are losing jobs and our surrounding states are gaining them," Ridgeway said.
Ridgeway spoke about a 'pass or fail' test Missouri faces, saying that 50 percent of manufacturing jobs specifically request locations in "right to work" states.
"Missouri will never even know those jobs exist," Ridgeway said.
Sen. Jane Cunningham, R-St. Louis County, said "We can not afford that when we are nearing 10 percent unemployment. I can not think of one thing that is more helpful to bringing jobs to Missouri than this issue."
Ridgeway said the bill also gives workers control over who represents them on the job.
"It gives the individual worker the right to say, 'No, I'm not being fairly represented," Ridgeway said.
Democratic Minority Leader Victor Callahan, D-Jackson County, spoke in opposition of the bill because, he said, it would weaken unions.
"[With unions,] the power of one becomes the power of many," Callahan said.
Others said union workers are the backbone of this country, and the strength of their support systems should not be diminished.
Sen. Robin Wright-Jones, D-St. Louis, spoke against "right to work" while it was still under committee review.
"We don't need anything that is going to change us or make it difficult for us to represent the worker," she said.
The Senate didn't vote on the bill. After considering amendments, the bill will come back to the Senate floor at the end of March.
Missouri Digital News is produced by Missouri Digital News, Inc. -- a non profit organization of current and former journalists.