She co-founded and co-directed The Brookings Institution Project on Internal Displacement for over a decade, served as senior adviser to the Representative of the United Nations Secretary-General on Internally Displaced Persons from 1994-2010, and now serves as senior adviser to The Brookings Institution – University of Bern Project on Internal Displacement.

She co-authored the first major study on internal displacement, Masses in Flight: The Global Crisis of Internal Displacement (Brookings, 1998) with Francis M. Deng, the first Representative of the Secretary-General and co-edited its second volume, The Forsaken People: Case Studies of the Internally Displaced (Brookings, 1998). The study proposed the creation of an international system for addressing the needs of internally displaced persons. In 2005, she and Deng were co-winners of the Grawemeyer Award for Ideas Improving World Order.

In 2003, she served as Public Member of the United States Delegation to the Organization for Security and Cooperation in Europe and in 1998 as a Public Member of the United States Delegation to the United Nations Commission on Human Rights. She has served as a consultant to governments, the UNHCR, the World Bank, the National Academy of Sciences, and a variety of non-governmental organizations. During the Carter administration, she served as a deputy assistant secretary of state for human rights in the Department of State and as senior adviser to the U.S. Delegation to the UN Commission on Human Rights and General Assembly. In 1985, she received the United States Information Agency Superior Honor Award for reopening U.S. educational, cultural, and information programs in Ethiopia during a difficult political period. She has also served as Honorary Secretary of the Parliamentary Human Rights Group (United Kingdom) and as Executive Director of the International League for Human Rights (New York).

She has published more than 100 articles on human rights and humanitarian issues and a series of opeds in leading newspapers. In 2002, she was awarded the DACOR (Diplomatic and Consular Officers, Retired -- State Department) Fiftieth Anniversary Award for Exemplary Writing on Foreign Affairs and Diplomacy, in particular on "refugees and internally displaced persons." In 2005, she received the Washington Academy of Sciences Award for Distinction in the Social and Behavioral Sciences. Most recently, Cohen is author of: “Disasters and Displacement: Gaps in Protection” (co-author with Megan Bradley), Journal of International Humanitarian Legal Studies, 2010; Improving the US Response to Internal Displacement: Recommendations to the Obama Administration and the Congress (co-author with Dawn Calabia), Brookings-Bern Project on Internal Displacement, June 2010; “Human Rights: A Means of Engaging North Korea,” 38 North, June 16, 2010; “Reconciling R2P with IDP Protection,” Global Responsibility to Protect, Vol. 2, Nos.1/2, 2010; “Mass displacement from conflict and one-sided violence: national and international response” (co-author with Francis Deng), SIPRI Yearbook 2009; “The Burma Cyclone and the Responsibility to Protect,” Global Responsibility to Protect, Vol. 1, No. 2, 2009; “Iraq’s Displaced: Where to Turn?” American University International Law Review, 2008; “Disaster Standards are Needed in Asia,” Brookings Northeast Asia Commentary, June 2008; “Humanitarian Imperatives are Transforming Sovereignty,” Northwestern Journal of International Affairs, Winter 2008; “Darfur Debated,” Forced Migration Review (Oxford: 2007); “Response to Hathaway,” Journal of Refugee Studies (Oxford), September 2007; “Measuring Indonesia’s Response to the Tsunami,” One Year After the Tsunami: Policy and Public Perceptions, Woodrow Wilson Center for International Scholars, 2006; “Developing an International System for Internally Displaced Persons,” International Studies Perspectives, May 2006; “Last Stand in Sudan?” Bulletin of the Atomic Scientists (co-author with William G. O’Neill), March/April 2006; and “Strengthening Protection of IDPs: The UN’s Role,” Georgetown Journal of International Affairs, Winter/Spring 2006.

Cohen is a Senior Associate at Georgetown University’s Institute for the Study of International Migration and Adjunct Associate Professor at the Academy on Human Rights and Humanitarian Law of American University’s Washington College of Law. She is Co-Chair of the Committee for Human Rights in North Korea, past Vice-Chair of the International Human Rights Law Group (now Global Rights) and serves on the boards or advisory committees of various human rights and humanitarian organizations, including the Jacob Blaustein Institute for the Advancement of Human Rights, the Committee on Conscience (Holocaust Memorial Museum) and the Washington College of Law Center for Human Rights and Humanitarian Law. She is a member of the Council on Foreign Relations, and is on the Editorial Board of Global Responsibility to Protect and on the International Editorial Advisory Board of the Journal of Refugee Studies (Oxford).

She has an honorary doctorate from the University of Bern (Switzerland), an M.A. “with distinction” from the Johns Hopkins School of Advanced International Studies (Washington DC and Bologna, Italy) and a B.A. from Barnard College (Columbia University, New York), where she majored in History and minored in Government, and which awarded her its Distinguished Alumna Award in 2005.