Governor Gavin Newsom vetoed California’s frontier-AI safety bill SB 1047 on September 29, 2024. Exactly one year later, on September 29, 2025, he signed SB 53, the Transparency in Frontier Artificial Intelligence Act - a narrower, disclosure-focused law authored by the same legislator, Senator Scott Wiener. Both dates are documented in official Governor’s office materials.
The pairing captures how US state AI regulation shifted in a single year, from a rejected bill that would have imposed pre-deployment safety duties keyed to a model’s size and training cost, toward a signed law built around published safety frameworks and whistleblower protection for the largest developers. See 2024-sb-1047-veto and 2025-sb-53-frontier-ai-act.