The Supreme Court struck a new anti-union note Wednesday during oral arguments that pointed toward a ruling against the Washington state teachers union in a First Amendment dispute over how it should collect fees from nonmembers.

At issue in Davenport v. Washington Education Association and Washington v. Washington Education Association is a 1992 state ballot initiative that requires unions to ask nonmembers to affirmatively “opt in” to pay the portion of agency fees that go toward the union’s political activities.