The future of public employee unions may be in the hands of Justice Antonin Scalia as the U.S. Supreme Court considers a case brought by Illinois home care workers who don’t want to pay fees to a union they don’t want to join.

Comments and questions from justices during arguments Jan. 21 in Harris v. Quinn revealed a closely divided court, with Scalia cast in the unusual role of swing justice. Not known as an ally of organized labor, the conservative Scalia nonetheless appeared sympathetic to the argument that the case could drastically weaken unions that have long been allowed to charge nonmembers fees to pay for collective bargaining that benefits all employees, including nonmembers.