In some ways, Scalia’s question was a (very) small victory for the unions. At least the conservative justice saw a state interest in allowing public workers to be represented by a union, and in ensuring the union’s minimal survival—though maybe no more than that.

Yet, Scalia’s implication missed an important fact: Many states want effective and well-resourced unions, even though those unions will be on the other side of the bargaining table. That much is apparent from California’s robust defense of its collective-bargaining law in Friedrichs, as well as the amicus briefs filed by 21 states and the District of Columbia and a list of cities, counties, elected officials, and school districts in support of California and the California Teachers Association. (I was one of the co-authors of an amicus brief on behalf of Labor Law and Labor Relations Professors in support of the state and union parties in this case.)

And there’s further proof in how many individual states have chosen to manage their employees through collective bargaining: States are not locked into a one-size-fits-all labor-relations model. If a state views unions as unhelpful partners, they are free to eliminate or curtail public-sector bargaining. Despite this, most states allow at least some public workers to bargain collectively. As a result, today about 35 percent of public-sector workers are union members. Furthermore, nearly half of states require or permit agency fees.

But what do states and other public employers gain from the existence of strong unions? During the Friedrichs argument, the solicitor general of California explained that his state’s collective-bargaining statute—which not only requires represented workers to pay agency fees, but also structures union representation in myriad other ways—was passed in response to “a long history in California in the ‘50s and 1960s of labor unrest.” California was not alone in this regard—many states first authorized public-sector bargaining in response to a wave of hugely disruptive strikes that took place in the 1960s and ‘70s. These strikes closed schools, stopped garbage pickup, ground public transit to a halt, and even left cities without the protection of firefighters and police. But implementing collective bargaining proved an effective antidote, and subsequent research has confirmed that collective bargaining curtails strikes and other disruptions in the public sector.

This result may seem counterintuitive; one might assume that eliminating public-employee unions would correspondingly eliminate public employees’ collective action. But this view misses what public unions can accomplish for their members: collecting and voicing workers’ priorities, pursuing them in bargaining, and enforcing the resulting contract. Not only do public employees value the improvements in wages and working conditions that unions win, but the opportunity to bargain itself makes workers more likely to buy into their employers’ missions and stay at their jobs. And, worker stability and voice are in turn linked to productivity gains, undermining Friedrichs’s counsel’s assumption that a strong union drives up spending. Even more important, when public unions fight for measures that help workers do their jobs safely and effectively—such as when firefighters bargain for better safety equipment or nurses bargain for lower staff-to-patient ratios—the public benefits too.