On September 1, 2011, Mariano-Florentino Cuéllar, a lawyer, scholar, and former official in the Clinton and Obama administrations, assumed the position of co-director of the Center for International Security and Cooperation (CISAC) at Stanford's Freeman Spogli Institute for International Studies (FSI).

An expert in administrative law, international security, and public health and safety, Cuéllar is Professor and the Deane F. Johnson Faculty Scholar at Stanford Law School, and is also professor (by courtesy) of political science. He is a longtime affiliated faculty member at CISAC and CISAC executive committee member. He has collaborated with or served on the boards of several civil society organizations, including the Haas Center for Public Service, Asylum Access, and the American Constitution Society.

Cuéllar has had an extensive record of public service since joining the Stanford Law School faculty in 2001. Recently, he served in the Obama Administration as Special Assistant to the President for Justice and Regulatory Policy. In that role, he led the Domestic Policy Council’s work on criminal justice and drug policy, public health and food safety, regulatory reform, borders and immigration, civil rights, and rural and agricultural policy. Among other responsibilities, he represented the Domestic Policy Council in the development of the first-ever Quadrennial Homeland Security Review, and coordinated the President’s Food Safety Working Group.

Before joining the White House staff, Cuéllar co-chaired the Obama-Biden Transition’s Immigration Policy Working Group. Earlier in his career, during the second term of the Clinton Administration, Cuéllar worked at the U.S. Department of the Treasury as Senior Advisor to the Under Secretary for Enforcement, focusing on countering financial crime, improving border coordination, and enhancing anti-corruption measures.

In July 2010, when Cuéllar left the Obama administration to return to Stanford, he also accepted an appointment from the President to the Council of the Administrative Conference of the United States, a non-partisan agency charged with recommending improvements in the efficiency and fairness of federal regulatory programs. In 2011, U.S. Secretary of Education Arne Duncan appointed Cuéllar to the Department of Education's Equity and Excellence Commission, which will examine the impact of school finance on educational opportunity and recommend ways school finance can be improved to increase equity and achievement.

Cuéllar graduated from Calexico High School in rural Southern California, going on to receive a BA magna cum laude from Harvard University in 1993, a JD from Yale Law School in 1997, and a PhD in political science from Stanford University in 2000. Cuéllar clerked for Chief Judge Mary M. Schroeder of the U.S. Court of Appeals for the Ninth Circuit from 2000 to 2001.

Cuéllar joins current CISAC co-director Siegfried S. Hecker, professor (research) of management science and engineering and FSI senior fellow, in leading one of the country’s preeminent university-based research centers on international security and cooperation.

He succeeds longtime co-director Scott D. Sagan, who has led the Center since 1998. Sagan, the Caroline S.G. Munro Professor of Political Science and FSI senior fellow, will continue as an important presence at CISAC and FSI, with plans to focus on policy-related research for the American Academy of Arts and Science's Global Nuclear Future Initiative, where he serves as the co-chair with Harvard’s Steven Miller. Sagan has been instrumental in building CISAC’s capacity as an international leader in interdisciplinary university-based research and training aimed at tackling some of the world's most difficult security problems.