It’s not to help low-wage workers.
At first glance, it makes little sense that labor unions would support minimum-wage increases. Union members don’t get paid the minimum wage, and if nonunion workers saw pay increases as a result of a minimum-wage increase, they would have less reason to unionize because the law would have raised their wages already.
For example, the market wage for an occupation might be $10 per hour. A sales pitch for a union recruiter in that occupation could be, “Join us, and we’ll bargain your wage up to $15 per hour.” But if the minimum wage is increased to $15 per hour for all workers across occupations, that sales pitch is no longer persuasive.
Yet unions are some of the strongest proponents of minimum-wage increases. The “Fight for $15” campaign has been supported by the AFL-CIO, for example. A constitutional amendment for a $15 minimum wage in Ohio is being supported by the SEIU.
Why are these unions pushing for legal changes that don’t affect their members’ wages and might make unions less relevant to low-wage nonmembers? Economists Jeffrey Clemens of UC San Diego and Michael Strain of AEI ask that question in a new paper. They find that, exactly as you’d expect, a higher minimum wage makes low-skilled workers less likely to join a union because they “treat the minimum wage as a substitute for the services of unions.” Unions nonetheless gain because workers who aren’t affected by the minimum wage become more likely to join.
Clemens and Strain estimate that “over the past decade, a one-dollar increase in a state’s minimum wage predicts a 5 percent increase in union membership among people ages 16–40.” They considered confounding variables, such as whether union membership was increasing anyway due to other factors, or whether the effect could be explained by general economic conditions or political factors. They find that these possible alternative variables do not explain the increase and write, “We find robust evidence that minimum wage increases had a causal impact on union membership rates.”
Roughly half of the increase in union-membership rates due to minimum-wage increases comes from public-sector workers, they find. Whether public or private, union membership increases among workers with bachelor’s degrees or higher levels of education when the minimum wage goes up. Public-sector or highly educated workers already make well above the minimum wage, so the reason they’re joining isn’t that they benefit from the policy change.
What Clemens and Strain find is that unions’ minimum-wage advocacy, despite being framed as an effort to benefit low-wage workers, helps unions recruit high-wage members. “These findings highlight that factors other than direct material benefit must be in play as a driver of the decision to become a union member in the wake of minimum wage increases,” they write.
One of those nonmaterial factors is political affiliation. Public-sector workers and highly educated workers are more likely to be Democrats than Republicans. In recruiting those workers, it would help unions to have a progressive reputation. One way to do that is by supporting progressive policies, such as increasing the minimum wage.
Clemens and Strain find that successful minimum-wage increases generate positive news coverage for unions that support those increases. “Over time, newspaper articles about unions have become less likely to focus on strikes, which are viewed negatively by the public, and more likely to connect unions and minimum wages, which are viewed positively by the public,” they write.
This paper suggests that unions have good reasons to act like progressive interest groups. Highly educated and public-sector workers, who are more likely to be progressive, respond positively to progressive advocacy and therefore become more likely to join unions.
Unions’ recruiting pitch isn’t about getting higher wages or benefits for their members. (Most workers in the U.S. don’t find that they would benefit from that.) It’s about joining an interest group whose values you share. And those values are just about always progressive.