US Department of State
Prior to joining Arent Fox, Ambassador Prosper was the US Ambassador-at-Large in charge of the Secretary of State’s Office of War Crimes Issues. He was appointed in 2001 by President George W. Bush and, after being unanimously confirmed by the US Senate, served until October 2005.
As the President’s envoy and senior diplomat, Ambassador Prosper traveled worldwide conducting diplomatic negotiations and consultations with heads of state, foreign ministers, and senior government officials from over 60 different countries. He also engaged foreign parliaments and multilateral and international organizations to build support for US policies. He regularly visited conflict zones in efforts to secure peace, stability, and the rule of law. In this capacity, Ambassador Prosper formulated and coordinated US policy responses to atrocities and attacks against civilians throughout the world. He reported directly to US Secretaries of State Colin Powell and Condoleezza Rice and advised the President of the United States, Secretary of Defense, Attorney General, National Security Advisor, Chairman of the Joint Chiefs of Staff, Director of the Central Intelligence Agency, White House Counsel and other senior US government officials. After September 11, 2001, Ambassador Prosper played a key role in developing policy to confront terrorism. He was also the chief US negotiator and lead diplomat responsible for engaging nations regarding their nationals held in Guantanamo Bay, Cuba and captured by US forces in combat.
US Department of State/US Department of Justice
Special Counsel and Policy Adviser/Special Assistant to the Assistant Attorney General
From 1999 to 2001, Ambassador Prosper worked in the US State Department, Office of the Secretary of State, where he served as a special counsel and policy adviser on war crimes issues. He was detailed from the US Department of Justice, where he served as Special Assistant to the Assistant Attorney General for the Criminal Division.
Lead Trial Attorney
From 1996 to late 1998, Ambassador Prosper was a war crimes prosecutor for the UN International Criminal Tribunal for Rwanda. While working and living in Rwanda for nearly three years in the aftermath of the genocide, he was appointed lead trial attorney and prosecuted Prosecutor vs. Jean-Paul Akayesu, the first-ever case of genocide under the 1948 Genocide Convention. He won additional convictions for crimes against humanity and broke new ground in international law by convincing the UN Tribunal, for the first time, to recognize rape as an act of genocide and a crime against humanity.
US Department of Justice, Office of the United States Attorney
Assistant US Attorney
From 1994 to 1996, Ambassador Prosper was an Assistant United States Attorney for the Central District of California in Los Angeles assigned to the Narcotics Section, Drug Enforcement Task Force, where he investigated and prosecuted major international drug cartels.
Los Angeles County District Attorney’s Office
Deputy District Attorney
Prior to becoming an Assistant US attorney, Ambassador Prosper was a Deputy District Attorney for Los Angeles, California from 1989 to 1994. His last two years in the DA’s Office were spent in the Hardcore Gang Division of the Bureau of Special Operations prosecuting solely gang-related murders.