Will ending the fees cripple or destroy public-employee unions? Who knows? Will unions become less effective in making labor-management relations harmonious? Who knows? Search the joint appendix in this case—nearly 700 pages of pleadings, docket entries, and opinions—and you won’t encounter even one piece of live testimony from union leaders or state officials. The record contains no testimony or studies by labor economists.

That’s because the challengers below—represented by the anti-union Center for Individual Rights—demanded that the lower courts rule against them on a bare record. Current Supreme Court precedent is flatly against them, and lower courts can’t overturn Supreme Court decisions. We want to hurry this case up to the high court, the challengers said; don’t slow us down with facts.

Now they have the case where they wanted it, they ooze confidence—because in the past four years, the conservative majority has twice signaled that it is tired of public-employee unions and wants a chance to radically rewrite the law in this area.

There are public-employee unions in all 50 states and the District, of course. But in the jurisdictions that Friedrichs would affect, the legislatures have opted for something called the “fair-share” or “agency fee” system. Under this system, a majority of public employees in a given “bargaining unit”—the school system, say, or the police agencies—can vote to designate a union as their “exclusive bargaining agent.” That union then must represent all the workers in the bargaining unit. Since public employees cannot be forced to join a union, that will include a number of non-members.

But representation takes time and money. Under existing law, unions cannot charge non-members with their share of costs for activity that qualifies as political; but they can require a fee for the “chargeable” expenses of representation—money spent, union lawyer Frederick told the Court, for such things as “research, legal representation, conferring and consulting, communicating with members, trying to ascertain what the positions of all the workforce are before the union presents a policy.” Under a 1977 case called Abood v. Detroit Board of Education, those charges are permitted to prevent non-members from “free riding”—gaining the benefits of representation without paying for them.

Abood admitted that imposing the fees “has an impact upon their First Amendment interests.” But as an employer, government can limit employee speech rights to some extent; in the case of the “agency shop,” the Court reasoned, “such interference as exists is constitutionally justified by the legislative assessment of the important contribution of the union shop to the system of labor relations established by Congress.”

That is, federal law allows states to choose agency agreements—and those that have done so justify that choice in practical terms. Good relations with the employees, the argument goes, depends on mechanisms by which their concerns can be heard. Many states had seen strikes by teachers and other public workers—including crucial ones like correctional officers, garbage workers, teachers, and police. Agency agreements, the states argue, allow the two sides to negotiate and agree without open conflict.