While much of Justice Alito’s majority opinion dealt with the fine contours of speech related to unions, it did have a brief discussion on compelled speech:
As we explained in Knox, “[t]he government may not prohibit the dissemination of ideas that it disfavors, nor compel the endorsement of ideas that it approves.” 567 U. S., at ___ (slip op. at 8–9); see also, e.g., R.A.V. v. St. Paul, 505 U. S. 377, 382 (1992); Riley v. National Federa tion of Blind of N.C., 487 U. S. 781, 797 (1988) West Vir ginia Bd. of Ed. v. Barnette, 319 U. S. 624 (1943); Wooley v. Maynard, 430 U. S. 705, 713–715 (1977). And “com pelled funding of the speech of other private speakers or groups” presents the same dangers as compelled speech. Knox, supra, at ___ (slip op. at 9). As a result, we ex plained in Knox that an agency-fee provision imposes “a ‘significant impingement on First Amendment rights,’” and this cannot be tolerated unless it passes “exacting First Amendment scrutiny.” 567 U. S., at ___ (slip op. at 9–10).