I research, write, and teach about foreign and national security policies related to the risks posed by nuclear weapons and nuclear energy.  My current research focuses on North Korea, the risks of new nuclear energy, and the intersection of climate change and national security.  I teach graduate courses on nuclear proliferation and weapons of mass destruction arms control.  As a former  policymaker, I am keen to help students understand the practical opportunities and challenges for decisionmaking in these areas.   As a writer, it is my mission to make these complex topics understandable to everyone.

I joined ESIA faculty in 2018, after leading the Proliferation Prevention Program at the Center for Strategic & International Studies (CSIS) for 8 years and a few years as a senior scholar at the Carnegie Endowment for International Peace.  Prior to that, I served in senior positions at the U.S. Arms Control & Disarmament Agency, the U.S. State Department, and the Congressional Research Service of the Library of Congress. 

I sit on the boards of key organizations in the field, including the Center for Arms Control & Nonproliferation, the Wisconsin Project on Arms Control, the PIR Center, and, previously, the Science & Security Board of the Bulletin of the Atomic Scientists.