A noted policy expert and former diplomat, she oversees the Bulletin‘s publishing programs, management of the Doomsday Clock, and a growing set of activities around nuclear risk, climate change, and disruptive technologies.

Before joining the Bulletin, Alexandra Bell served as the Deputy Assistant Secretary for Nuclear Affairs in the Bureau of Arms Control, Deterrence, and Stability (ADS) at the U.S. Department of State. There she managed the Offices of Strategic Stability and Deterrence and Multilateral and Nuclear Affairs. From 2017 to 2021, Bell was the Senior Policy Director at the Center for Arms Control and Non-Proliferation and the Council for a Livable World. Previously, Bell served as a Senior Advisor in the Office of the Under Secretary of State for Arms Control and International Security and as an Advisor in ADS, then named the Bureau of Arms Control, Verification and Compliance. Before joining the Department of State in 2010, she worked on nuclear policy issues at the Ploughshares Fund and the Center for American Progress.