Senate negotiators are weighing a duty-of-care law letting federal courts block unsafe model releases and preempting state AI laws.

Thune, Cruz and Klobuchar are negotiating a bill obligating frontier developers to design against catastrophic risks such as a model helping someone build a nuclear or biological weapon, giving the government a route through federal courts to stop a release. The same measure would bar states from enforcing their own laws on those risk categories, setting it directly against California's recently signed chatbot rules. It would apply only to the most capable models, meaning Google, Anthropic and OpenAI (Reuters). Preemption is the part with teeth, and it's the part that makes the bill attractive to the labs it regulates.