Squassoni directs the Proliferation Prevention Program at the Center for Strategic and International Studies. Prior to joining CSIS, she was a senior scholar at the Carnegie Endowment for International Peace. From 2002 to 2007, she advised Congress as a senior specialist in weapons of mass destruction at the Congressional Research Service. Her other government service includes positions at the State Department and Arms Control and Disarmament Agency in nuclear nonproliferation and policy planning.