He recently completed a fellowship with the Open Society Institute, in which he undertook a study of the law of U.S. citizenship. He has written widely on dual citizenship, naturalization policy, and the role of federalism in immigration policymaking. Spiro has also served as a law clerk to U.S. Supreme Court Justice David Souter and as an attorney-adviser in the Office of the Legal Adviser, U.S. Department of State. In addition, he has studied the role of non-governmental organizations in international decision-making while holding positions at the Carnegie Endowment for International Peace and on the staff of the National Security Council. - [ Ed. changed 1/5/06 ]