Conservatives on the Supreme Court have been signaling for years that they would like to destroy public-sector unions. On Wednesday, they handed down a ruling that aims to do just that. But the justices and right-wing groups that pushed for this outcome could soon find that it will not be so easy to suppress teachers, social workers and other government employees who in recent months have taken to the streets to demand raises and better working conditions.

Overturning a unanimous 41-year-old decision, the court ruled 5 to 4 that state governments could not force public employees who don’t join unions to pay fees that support collective bargaining. More than 20 states require these so-called fair-share or agency fees, which the court has upheld several times since that earlier ruling.

But writing for the majority, Justice Samuel Alito Jr. said that the court had been wrong all this time and was violating the First Amendment rights of government workers by insisting they support unions whose positions they might not agree with. Or, in other words, someone’s free speech rights can be violated by making the worker pay a union to do the very thing that it was formed to do. Right. It’s hard not to agree with Justice Elena Kagan, who wrote in a sharp dissent that the majority was “weaponizing the First Amendment, in a way that unleashes judges, now and in the future, to intervene in economic and regulatory policy.”