Why California’s SB 1047 Was Vetoed

SB 1047, the Safe and Secure Innovation for Frontier Artificial Intelligence Models Act, passed the California Legislature in 2024 but did not become law. Governor Gavin Newsom returned it unsigned on September 29, 2024. The proposal would have established obligations for developers of models above specified compute and cost thresholds, required safety and security protocols, addressed catastrophic-risk testing and incident response, and created state oversight mechanisms. It also included provisions concerning shutdown capability and whistleblower reporting. Because the governor vetoed the bill, those provisions did not take effect as SB 1047. In his veto message, Newsom said the bill’s size-based trigger did not adequately account for whether a system was deployed in a high-risk environment, involved critical decision-making, or used sensitive data. He argued the approach could impose stringent standards on systems with basic functions merely because they belonged to a large model. The message also acknowledged catastrophic risks and argued California should use a more flexible, evidence-based approach. The veto was therefore framed as a disagreement over scope and design, not a claim that AI risks were unimportant. Debate over SB 1047 involved competing concerns about catastrophic risk, innovation, open-source development, state oversight, and whether compute thresholds reliably identify dangerous capabilities. Supporters emphasized safety protocols and accountability for powerful models. Critics argued the bill could be overly broad, create uncertainty, or burden development. Those arguments are context for the legislative debate; they are not a substitute for the bill text or the governor’s message. California later enacted SB 53, the Transparency in Frontier Artificial Intelligence Act, in 2025. SB 53 created a different framework with transparency, incident-reporting, and whistleblower provisions for covered frontier developers. It should not be described as SB 1047 taking effect under a new name. To understand the policy shift, compare each enacted text, its scope and effective dates, then distinguish operative law from proposed measures and executive statements.