In February 2017, then-governor of Missouri Eric Greitens (R) signed a right-to-work bill drafted by the state’s GOP-controlled legislature. The bill made Missouri the 28th right-to-work state in the country and the sixth state to pass such legislation since 2012.

But the bill isn’t yet law, thanks to petitioners who gathered over 250,000 signatures to place the measure before voters as a referendum.

Missouri voters will head to the polls Tuesday to cast ballots on Proposition A, an up-or-down referendum on the right-to-work bill. If “no” votes prevail, the bill will die, giving unions a much-needed win during an administration that has made it their priority to cede power away from the workers in order to reward those at the top.

It also would be the first chance for voters to weigh in on union power since the U.S. Supreme Court ruled in Janus v. AFSCME last June that public sector employees cannot be compelled to pay union dues.

Right-to-work laws allow workers to opt out of paying union dues while still enjoying the benefits of a union contract, like higher wages, benefits, and protection against arbitrary discipline. The result is a “free-rider” problem, which drives down union membership rates, because if workers can get something for nothing, many of them will choose to do so.

Supporters of right-to-work legislation argue that the laws simply ensure that no worker is forced to be a member or pay fees to a political group with which they do not agree. That, however, is already forbidden by federal law. Unions are required to bargain on behalf of every worker in a unionized shop, regardless of whether or not a particular worker joins the union.

In order to avoid the free-rider problem, many union contracts provide for “agency fees” or “fair share fees,” which require non-members to contribute their share of   costs of negotiating and overseeing union representation.

State right-to-work laws make it more difficult to collect these fees, restricting union resources and hindering a union’s ability to negotiate for better wages, benefits, and working conditions for workers.

According to the Economic Policy Institute, there will be roughly 60,000 fewer union members in the Missouri private sector if the state adopts this law.

“Without collective bargaining we’re at risk of losing our health benefits, our retirement savings and being forced to take a pay cut,” Quiema Spencer, a 39-year-old pipe-fitter from Kansas City, Missouri told The Wall Street Journal. “I can’t afford that with the cost of living going up.”

The decline of union membership harms workers, both union and nonunion alike. Right-to-work states have lower rates of employer-sponsored health insurance and lower employer-sponsored pensions.

Right-to-work laws are also responsible for creating an atmosphere that forces families who work full-time jobs to live paycheck-to-paycheck or work multiple jobs in order to make ends meet.

In states where right-to-work laws are currently on the books, wages are roughly 3.1 percent lower — equal to about $1,560 less per year — than those in states without right-to-work laws. Multiple studies have confirmed that the decline of collectively bargained union contracts has led to the hollowing out of workers earnings. In one long term study from Princeton University, researchers found that unions have consistently “provided workers with a 10- to 20-percent wage boost over their non-union counterparts over the past eight decades.”

“What we’re simply trying to do in this study is to be able to say something systematic, historically, whether there seems to have been an inverse relationship between unionization and inequality, so that when unions were strong, inequality tended to be lower,” one of the researchers wrote. “A strong lesson is that when unions were strong and they were growing, they were organizing the less-skilled workers and raising their wages, and that tends to reduce inequality.”

Luckily for Missouri workers, union support against the proposition has been particularly strong. We Are Missouri, an anti-right-to-work group, has spent $15.2 million in an effort to block the bill from becoming law. That is roughly five times the amount two groups who support the law have spent, according to The Wall Street Journal.

About the Author: Rebekah Entralgo is a reporter at ThinkProgress. Previously she was a news assistant on the NPR Business Desk. She has also worked for NPR member stations WFSU in Tallahassee and WLRN in Miami.

This article was originally published at ThinkProgress on August 7, 2018. Reprinted with permission.