Question: Under what president did William Cohen serve as Secretary of Defense in the years following the death of Esequiel Hernández Jr.?
Context: The Defense Acquisition Board (DAB) is the senior advisory board for defense acquisitions in the Department of Defense of the United States of America.  The board is chaired by the Under Secretary of Defense for Acquisition, Technology and Logistics and includes the Vice Chairman of the Joint Chiefs of Staff, the Service Secretaries (Secretary of the Army, Secretary of the Navy & Secretary of the Air Force), and a number of Under Secretaries of Defense.  The DAB plays an important role in the Defense Acquisition System.  Members of this board are responsible for approving the Major Defense Acquisition Programs (MDAPs) and serve as the most important executive review of expensive acquisition projects that would have potentially large impacts on how wars are fought — things like new tanks, fighter aircraft, or C3 systems. William Sebastian Cohen (born August 28, 1940) is an American politician and author from the U.S. state of Maine.  A Republican, Cohen served as both a member of the United States House of Representatives and Senate, and as Secretary of Defense (1997–2001) under Democratic President Bill Clinton. Kenneth Davison McClintock Hernández (born January 19, 1957) served as the twenty-second Secretary of State of Puerto Rico, one of the four longest serving in that post.  McClintock served as co-chair of Hillary Clinton’s National Hispanic Leadership Council in 2008, co-chaired her successful Puerto Rico primary campaign that year and served as the Thirteenth President of the Senate of Puerto Rico until December 31, 2008.  He chaired Luis Fortuño’s Incoming Committee on Government Transition in 2008 and the Outgoing Committee on Government Transition in 2012, the only Puerto Rican to serve in both capacities.  He was sworn into office as Secretary of State on January 2, 2009, by Chief Justice Federico Hernández Denton, fulfilling the role of Lieutenant Governor (first-in-line of succession) in the islands. William Cohen (born 1940) is an American author and politician who served as Secretary of Defense (1997–2001) under Bill Clinton. The U.S. Commission on National Security/21st Century (USCNS/21), also known as the Hart-Rudman Commission or Hart-Rudman Task Force on Homeland Security, was chartered by Secretary of Defense William Cohen in 1998 to provide a comprehensive review of US national security requirements in the 21st century.  USCNS/21 was tasked "to analyze the emerging international security environment; to develop a US national security strategy appropriate to that environment; and to assess the various security institutions for their current relevance to the effective and efficient implementation of that strategy, and to recommend adjustments as necessary". On 8 December 2008, the Genocide Prevention Task Force, co-chaired by Madeleine Albright, a former US Secretary of State, and William Cohen, a former US Secretary of Defense, released its final report which concludes that the US government can prevent genocide and mass atrocities in the future. The Ballad of Esequiel Hernández is a 2007 American documentary film that investigates the murky killing of Esequiel Hernández Jr by US Marines.  It is written and directed by Kieran Fitzgerald and narrated by Tommy Lee Jones. Marc Isaiah Grossman (born September 23, 1951) is an American former diplomat and government official.  He served as United States Ambassador to Turkey, Assistant Secretary of State for European Affairs, and Under Secretary of State for Political Affairs.  He was most recently the United States Special Representative for Afghanistan and Pakistan and is currently a Vice Chairman of The Cohen Group, a business consulting and lobbyist firm of former Defense Secretary William Cohen, and a member of the German Marshall Fund board of trustees. Leonard Cohen was a Canadian singer-songwriter and poet who was active in music from 1967 until his death in 2016.  Cohen released 14 studio albums and eight live albums during the course of a recording career lasting almost 50 years, throughout which he remained an active poet.  His entire catalogue is available on Columbia Records.  His 1967 debut "Songs of Leonard Cohen" earned an RIAA gold record; he followed up with three more highly acclaimed albums: "Songs from a Room" (1969), "Songs of Love and Hate" (1971) and "New Skin for the Old Ceremony" (1974), before allowing Phil Spector to produce "Death of a Ladies' Man" for Warner Bros.  Records in 1977.  Cohen returned to Columbia in 1979 for "Recent Songs", but the label declined to release his next album, "Various Positions" (1984) in the US, leaving it to American shops to import it from CBS Canada.  In 1988, Columbia got behind Cohen again and gave full support to "I'm Your Man", which brought his career to new heights, and Cohen followed it with 1992's "The Future".  Cohen then took a nine-year hiatus, and returned with "Ten New Songs" in 2001, which he made with Sharon Robinson, following this with "Dear Heather" (2004).  In 2008 Cohen began touring for the first time in 15 years and, as well as the release of several live albums, he released "Old Ideas" (2012), which peaked at number three on the "Billboard" 200 albums chart.  This was the highest ranking ever for a Leonard Cohen album, and it became his first to top the Canadian Albums Chart, a feat he repeated with his followup, "Popular Problems", released in 2014.  His live albums included "Live Songs" (1973), "" (1994), "Live in London" (2009), "Songs from the Road" (2010), from his 2008–2009 world tour, and "Live at the Isle of Wight 1970" (2009). Esequiel Hernández Jr. (May 14, 1979May 20, 1997) was an 18-year-old American high school student killed on May 20, 1997 by United States Marines in Redford, Texas, located approximately one mile from the United States–Mexico border. <ref name="Gwynne/Marfa"> </ref> Hernández was the first American civilian to be killed by active United States Armed Forces while they were on duty since the student massacre at Kent State University in 1970 and led to Defense Secretary William Cohen issuing a temporary suspension of troop patrols near the U.S.–Mexico border.  The shooting inspired the 2005 movie "The Three Burials of Melquiades Estrada" by Tommy Lee Jones, and the 2007 documentary "The Ballad of Esequiel Hernandez".
Answer: Bill Clinton