He was appointed United States Special Envoy for Sudan on March 31, 2011. Immediately preceding his tenure as Special Envoy, he served as US Senior Adviser on North-South Negotiations, where he led the US team focused on supporting on-going negotiations between the parties to Sudan’s 2005 Comprehensive Peace Agreement. He previously worked as an adjunct senior fellow for Africa policy studies at the Council on Foreign Relations (CFR). He is also an adjunct professor at Georgetown University. From 1999 to 2003, he was executive director of the Global Interdependence Initiative at the Aspen Institute.