Labor unions negotiate higher wages and better benefits for union members. That’s fine – that’s their purpose and it’s why some people choose to join unions and pay union dues.

The unions have to perform a delicate balancing act. If they don’t push for better wages and benefits for their members, then workers will have less of an incentive to join unions. But, as unions attain better wages and benefits for their workers, non-union labor starts to look much more attractive to employers and so employers will tend to prefer to hire non-union labor. If union labor is more productive than non-union labor, then the fact that union labor is more costly might not be a problem.

But what’s a union to do when non-union labor is both cheaper and as productive as union labor?

The answer is to ask the government to impose artificial costs on non-union labor so that it isn’t cheaper. Unions do this under the guise of “concern for all workers,” but it’s actually concern for union workers.

This is why, for example, unions back minimum wage hikes despite the fact that union workers tend to make far more than the minimum wage. If non-union workers aren’t allowed to sell their labor for less than union workers, then employers will be less likely to hire non-union workers. It is also why unions support “paid sick leave” legislation.

There’s no question that people should be paid for the work they do. Paid sick leave is a perk that many unions have attained for their workers wherein union labor gets paid even when it’s not working. Of course, this makes non-union labor (workers who are only paid for work they do) more attractive to employers. But if the government forced employers to provide paid sick leave to all workers, then all of a sudden, non-union labor isn’t as attractive to employers.

If the value unions provide their workers is greater than the costs they impose on their workers, then workers will voluntarily join unions in droves. But unions have been unable to demonstrate that they can provide value. So now they turn to government to reduce their competition by making non-union labor less attractive. That sounds a lot like the tactics the robber barons employed that gave rise to unions in the first place.

Antony Davies is an associate professor of Economics at the Palumbo Donahue School of Business at Duquesne University.