In the State of Washington, unions may negotiate an "agency shop" agreement with an employer, allowing union officials to collect agency fees from employees who aren't members of the union. Washington law permits the union to spend excess money collected on political activities that have nothing to do with the collective bargaining process. Until recently, the law placed the burden on nonmembers to object to this use of their money. Recognizing the unfairness of this arrangement, Washington voters adopted an initiative that forbids the union from using non-members' fees for political purposes without the nonmembers' affirmative consent. Perversely, unions sued, alleging this provision impinged on the union's First Amendment rights to "free association." In this brief, authored by former Thomas clerk and First Amendment expert Erik Jaffe, we argue that the unions have it exactly backwards: the real First Amendment rights at stake are those of persons who haven't joined a union and don't want to contribute to the union's political activities. Those persons have a clear constitutional right to remain silent and unassociated with union political activities, and the Washington initiative protects that right. By contrast, unions have no constitutional right whatsoever to assume, based on a fictitious "association" with nonmembers, that persons unaffiliated with the union automatically "consent" to the use of their hard earned money to promote union politicking. The Cato Institute is joined by the Reason Foundation and the Center for Individual Freedom.