This post originally appeared in the New York Times Room for Debate forum on March 12, 2015.

“Right-to-work” laws deny unions the money they need to help employees bargain with their employers for better wages, benefits and working conditions. So it’s not surprising that research shows that workers in “right-to-work” states have lower wages and fewer benefits, on average, than workers in other states.

Under federal law, no one can be forced to join a union as a condition of employment, and the Supreme Court has made clear that workers can’t be forced to pay dues used for political purposes. Right-to-work goes one step further and entitles employees to the benefits of a union contract — including the right to have the union take up their grievance if their employer abuses them — without paying any of the cost.

This means that if a worker who does not pay a union representation fee is fired, the union must prosecute that worker’s grievance just as it would a dues-paying member’s, even if it costs tens of thousands of dollars. Non-dues-paying workers would also receive the higher wages and benefits their dues-paying coworkers enjoy. Right-to-work laws have nothing to do with whether people can be forced to join a union or contribute to political causes they don’t support; that’s already illegal. The only freedom workers would receive is the ability to get something for nothing.

But this comes at a substantial cost. As compared with non-right-to-work states, wages in right-to-work states are 3.2 percent lower on average, or about $1,500 less a year. Workers in right-to-work states were less likely to have employer-sponsored health insurance and pension coverage. This does not just apply to union members, but to all employees in a state.

Where unions are strong, compensation increases even for workers not covered by any union contract, as nonunion employers face competitive pressure to match union standards. Likewise, when unions are weakened by right-to-work laws, all of a state’s workers feel the impact.