He has been a grantee of the Program on Peace and International Cooperation of the John D. and Catherine T. MacArthur Foundation and a Visiting Fellow at the Center of International Studies of the Woodrow Wilson School at Princeton University. He has also taught at Princeton University's Woodrow Wilson School, the University of Phnom Penh Faculty of Law, Benjamin N. Cardozo School of Law, the New School for Social Research, Rutgers University School of Law, and various other universities in the US and abroad. He has been a consultant to the MacArthur and Asia foundations and to international agencies and organizations, including UNDP. He serves on the board of directors of numerous organizations and is active in several leading professional associations, including the American Society of International Law, the International Law Association, the International Studies Association, and the American Bar Association. He is President of the American Committee for the International Service for Human Rights?USA and represents the International Secretariat of that organization at the United Nations.
In 1992-93, he served as head of human rights education, training and information for the United Nations Transitional Authority in Cambodia (UNTAC). Previously, he was Assistant to the Independent Jurist, United Nations Mission for the Referendum in the Western Sahara; Director of the Program in International Law and Human Rights at Cardozo School of Law, program officer for international human rights at the Ford Foundation; senior program specialist in the Division of Human Rights and peace of the United nations Educational, Scientific and Cultural Organization (UNESCO in Paris); and senior staff at the International Institute of Human Rights, in Strasbourg.
His publications relate to various aspects of international law and organizations, peacekeeping, development and human rights. Recently he co-edited (with Burns Weston) and contributed to The Future of International Human Rights (Transnational Publishers, 1999).