In a case that threatened the future of public-employee unions, the U.S. Supreme Court on Monday ruled so-called agency fees charged to certain nonunion members violate those members’ First Amendment rights.

The high court stopped short of barring all public-employee unions from charging agency fees to nonmembers. The employees in the case before the court—Illinois home care workers—were not “full-fledged” public employees, the court said.

Justice Samuel Alito Jr., writing for the majority, said there were key differences between the personal care workers at issue and “full-fledged” public employees, including the government’s authority with respect to those employees.

Extending the case law “to encompass partial-public employees, quasi-public employees, or simply private employees would invite problems,” Alito wrote, joined by Chief Justice John Roberts Jr. and justices Antonin Scalia, Anthony Kennedy and Clarence Thomas.

“If we accepted Illinois’ argument, we would approve an unprecedented violation of the
bedrock principle that, except perhaps in the rarest of circumstances, no person in this country may be compelled to subsidize speech by a third party that he or she does not wish to support,” Alito wrote.

Justice Elena Kagan, joined by justices Ruth Bader Ginsburg, Stephen Breyer and Sonia Sotomayor, dissented.