Mallory Stewart is the Assistant Secretary for the Bureau of Arms Control, Deterrence, and Stability (ADS) at the U.S. Department of State. She joined the bureau in 2022, after serving as a Special Assistant to President Biden and Senior Director for Arms Control, Disarmament, and Nonproliferation at the National Security Council since January 2021. Prior to joining the NSC, she was the Senior Manager for Global Nuclear Security and Nonproliferation at the Center for Global Security and Cooperation in Sandia National Laboratories. While at Sandia, she helped lead Sandia’s Cooperative Monitoring Center in its efforts to facilitate scientific engagement for global security. From 2015 to 2017, Ms. Stewart was Deputy Assistant Secretary for Emerging Security Challenges and Defense Policy in what was then called the Bureau of Arms Control, Verification and Compliance. In that role, she oversaw the Office of Emerging Security Challenges and the Office of Chemical and Biological Weapons Affairs. Before that, Ms. Stewart was an attorney adviser in the Department of State’s Office of the Legal Adviser, beginning in 2002. During that time, she worked on numerous legal issues related to nonproliferation sanctions, weapons of mass destruction and conventional arms control, missile defense, and space in the Office of Nonproliferation and Arms Control. She also served in the Office of Treaty Affairs, and she represented the United States before the Iran-U.S. Claims Tribunal as an attorney in the Office of Claims and Investment Disputes. Ms. Stewart was the State Department lawyer for the U.S. delegation that negotiated the Ballistic Missile Agreements with Poland and Romania, and she was the lead lawyer on the 2013 U.S.-Russian Framework for the Elimination of Syrian Chemical Weapons. For her work on that issue, Ms. Stewart was a recipient of the Secretary of State’s 2014 Award for Excellence in International Security Affairs. Ms. Stewart has also worked as a Nonresident Fellow at the Stimson Center, an Adjunct Assistant Professor at Georgetown University’s School of Foreign Service, and as an associate at the law firm of Sullivan & Cromwell. She holds an A.B. from Harvard College and a J.D. from Stanford Law School.