The Supreme Court has ruled, 5-4, in the Janus case that public-sector unions may not collect “fair-share” fees from workers who benefit from union contracts but choose not to join the union as dues-paying members.

This in effect extends “right to work” principles to the entire public sector, the largest source of union growth in recent years, for schoolteachers, nurses, cops, firefighters, and myriad other public workers, some 17 million in all.

The decision, in the short run, will weaken unions such as SEIU, AFSCME, and the teachers’ unions. However, as shown by recent successful actions by teachers in several red states, public-worker political consciousness is on the rise, and so is popular support for them.

Public appreciation of the value of collective bargaining is growing generally. More than three in five Americans have a favorable view of unions, with two-thirds of young people supporting unions.

After Janus, public-sector union members will have to redouble efforts to persuade their free-riding brothers and sisters of the value of strong unions. They will be helped in this enterprise by the worker-bashing of right-wing state governments, the Trump administration, and now the Supreme Court.

It would be an exaggeration to call Janus a blessing in disguise—it is one more outrage by a Supreme Court taking advantage of Neil Gorsuch’s stolen seat. But the organizing that occurs in the wake of Janus will bring out the best in trade unionism.