During the administration of President Bill Clinton, Vahan served on the White House think tank at the Institute for Economic Strategy, where he researched, analyzed, and wrote reports on various US issues in trade relations. Vahan returned to Washington, DC as Secretary of the United States Department of Justice, at the U.S. Attorney’s Office, where he worked on the prosecution of the main criminal cases of the Federal courts in the USA, including the main international funds of money laundering and drug trafficking cases.