Cahill Files Answering Brief in Ninth Circuit on Behalf of Leading Social Media Platform
March 23, 2026
On March 11, 2026, Cahill filed an answering brief in the U.S. Court of Appeals for the Ninth Circuit on behalf of a leading social media platform challenging AB 2655, a California statute that would force covered social media platforms to remove or label certain AI-generated political speech about elections—so-called “deep fake” content—that the State of California deems false or misleading. The answering brief asserts that AB 2655 is preempted by the immunity afforded to interactive computer service providers under Section 230(c)(1) and Section 230(c)(2)(B) of the federal Communications Decency Act.
In August 2025, Cahill prevailed on summary judgment in the Eastern District of California, successfully arguing that AB 2655 treats covered platforms as publishers of third-party content and impermissibly substitutes the State’s judgments about what content is permissible on covered platforms for those of the platforms. The district court permanently enjoined AB 2655’s enforcement and California appealed to the Ninth Circuit. On appeal, Cahill argues that the statute impermissibly encroaches on the quintessential editorial activities of covered platforms, in direct contravention of Section 230. Eleven amicus briefs have been filed in the Ninth Circuit in support of the Appellees’ challenge to AB 2655.
To read the full brief, click below.