Former Secretary of Defense Robert Gates is the only person in U.S. history to be asked to remain in that office by a newly elected president. President Barack Obama was the eighth president Gates served. He previously served under President George W. Bush. On Gates' last day in office, Obama awarded him the Presidential Medal of Freedom, America's highest civilian honor. An Eagle Scout and president of the Boy Scouts of America, Gates is the author of "Duty: Memoirs of a Secretary at War," a profoundly personal story and an insightful look into two administrations and the wars that defined them. He was interviewed by Mark Wolf, NCSL's publications editor.