In September 2024, California enacted a law imposing significant restrictions on social media access. Among the other things, the law would bar minors from accessing any social media site with a personalized feed unless they obtain parental consent. NetChoice, a trade organization representing several social media companies, filed a lawsuit arguing that the act would violate its members’ First Amendment rights.

A federal district court agreed with NetChoice in part and blocked some aspects of the law. But the Court upheld the “age-gating” provision for personalized social media feeds. The court held that this provision did not necessarily restrict the speech of social media companies. The court relied on the premise that “restrictions on a private speaker’s ability to compile and organize third-party speech implicate speech rights only if those restrictions impair the speaker’s own expression.” And the court took a narrow view of what qualifies as a social media site’s “own expression,” holding that an algorithm responding to a user’s activity would not qualify as a social media site’s own expression.

NetChoice has now appealed to the Ninth Circuit, and Cato has filed an amicus brief in support of NetChoice. In our brief, we explain that the district court vastly underestimated the scope of what entails a “speaker’s own expression.” As the Supreme Court held just last year in Moody v. NetChoice, the First Amendment protects the act of “compiling and curating others’ speech.” That is true whether or not a social media company agrees with any particular speech it curates. Indeed, it is true whether or not readers believe that a social media company agrees with any particular speech it curates. The Supreme Court in Moody was unequivocal: “major social-media platforms do not lose their First Amendment protection just because no one will wrongly attribute to them the views in an individual post.”

Despite Moody’s clear command, the district court instead relied on a much older Supreme Court precedent, PruneYard Shopping Center v. Robins (1980). In that case, the Supreme Court held that it did not violate the First Amendment to force a private shopping center to host political pamphleteers. Some courts have interpreted PruneYard as standing for the broad proposition that a compulsion to host speech does not violate the First Amendment unless it would create the false appearance of endorsement. But Moody squarely rejected that interpretation, making clear that the shopping mall lost in PruneYard only because the mall “was not itself engaged in expression.” In other words, the mall made no claim that it wanted to curate the speech that its shoppers experienced.

Our brief sums up the limited scope of PruneYard as clarified by Moody: If a mall is only concerned with selling wares and not with controlling what its patrons see and hear, it is not compiling and curating others’ speech. PruneYard stands for no more than that. If a mall decided to turn its space into not just a venue for shopping but also for speeches, demonstrations, and art exhibitions, it would win a First Amendment challenge to a compulsion to host any speaker it did not wish to host.

Since social media sites compile speech, they are “engaged in expression.” A law that limits a social media site’s freedom to welcome the visitors it wants to welcome inflicts a First Amendment injury. Our brief urges the Ninth Circuit to make this principle clear and reverse the district court in part.