Mariano-Florentino Cuéllar is president of the Carnegie Endowment for International Peace (from 2023) and a former Justice of the Supreme Court of California (2015–2021). A Stanford Law emeritus professor, he co-led the California Policy Working Group on AI Frontier Models in 2025. His background spans US high-court jurisprudence and AI governance.
Background
Before joining the bench, Cuéllar was a professor at Stanford Law School, where he is now emeritus. He was appointed to the Supreme Court of California by Governor Jerry Brown in 2015 and served until 2021, when he resigned to return to academia and subsequently moved to the Carnegie Endowment.
In the Obama administration, Cuéllar served as Assistant to the President for Justice and Regulatory Policy (2009–2010) and as Chair of the White House Domestic Policy Council for Immigration Policy. His work on technology and regulation predates his focus on AI.
His scholarship covers administrative law and regulatory process, AI governance (including co-authored work on AI and constitutional law), and international order and technology.
Roles
Carnegie Endowment
Cuéllar has been president of the Carnegie Endowment for International Peace since 2023. During his tenure, Carnegie has expanded its AI policy work, including the AI Governance Lab and grant support for AI safety research.
California Policy Working Group on AI Frontier Models (2025)
Cuéllar co-led the California Policy Working Group on AI Frontier Models with Jennifer Chayes and Fei-Fei Li. The academic-policy working group produced the California Report on Frontier AI Policy. His prior service as a California Supreme Court Justice was cited as a source of credibility for the group with state policymakers.
Positions and statements
Cuéllar's profile in AI policy combines high-court jurisprudential experience, administrative-law background, the international-affairs framing associated with Carnegie, and a Hispanic and Mexican-American perspective on immigration and technology policy.
Relationships
- supports: The California Report on Frontier AI Policy — co-lead.
- leads: Carnegie Endowment for International Peace.
- collaborates-with: Li Fei-Fei / Jennifer Tour Chayes.
- related: California SB 53 — Transparency in Frontier AI Act — academic framework descendant.
- related: AI Liability — his constitutional and administrative-law lens informs liability-regime discussions.