From 2004 to 2006, Lange, a career member of the Senior Foreign Service with rank of Minister-Counselor, served as Deputy Inspector General of the State Department overseeing audits, inspections and investigations.

Lange served from 2003 to 2004 as Deputy Coordinator in the Office of the U.S. Global AIDS Coordinator, which oversees all U.S. Government international HIV/AIDS assistance. He worked with the Coordinator to establish the office from its inception and represented the United States at international meetings on AIDS.

From 2002 to 2003, Lange served as Associate Dean in the Leadership and Management School at the Foreign Service Institute. He directed the Senior Seminar, which was the flagship interagency executive development program for senior leaders from U.S. foreign affairs and national security agencies and military services.

From 1999 to 2002, Lange served as U.S. Ambassador to the Republic of Botswana. He oversaw operations of seven U.S. Government agencies, including provision of assistance for the care, prevention and treatment of AIDS in Botswana (which has one of the highest HIV infection rates in the world). Ambassador Lange simultaneously served as the Special Representative of the Secretary of State to the Southern African Development Community, headquartered in Gaborone.

Lange served as Deputy Chief of Mission at the U.S. Embassy in Dar es Salaam, Tanzania, from 1997 to 1999 and headed the Embassy as Charge d'Affaires from January to September 1998. He received the Distinguished Honor Award of the Department of State for "skilled leadership" and "extraordinary courage" in the aftermath of the terrorist bombing of the Embassy on August 7, 1998.

While at the U.S. Mission to the United Nations in Geneva, Switzerland, from 1991 to 1995, Lange managed U.S. humanitarian and refugee assistance to international organizations. He has worked in the State Department Bureaus of African Affairs, Western Hemisphere Affairs and Management in Washington and at the American Embassies in Lome, Togo; Paris, France; and Mexico City, Mexico. He joined the diplomatic service in 1981 and has received two Superior Honor Awards and two Senior Performance Awards.

Lange has authored articles on the Dar es Salaam bombing, crisis management, and military-civilian coordina-tion in providing humanitarian assistance. He is a "distinguished graduate" of the National War College (1996) and a graduate cum laude of the University of Wisconsin Law School (1975). He was admitted to the bar in Wisconsin (1975) and New York (1979). He speaks French and Spanish.