JUSTICE ALITO delivered the opinion of the Court. Under Illinois law, public employees are forced to subsi dize a union, even if they choose not to join and strongly object to the positions the union takes in collective bar gaining and related activities. We conclude that this arrangement violates the free speech rights of nonmem bers by compelling them to subsidize private speech on matters of substantial public concern. We upheld a similar law in Abood v. Detroit Bd. of Ed., 431 U. S. 209 (1977), and we recognize the importance of following precedent unless there are strong reasons for...