Question: What melody from the French opera "Geneviève de Brabant" is used by Western Illinois University before all of it's football games and the United States Marine Corps as it's military hymn?

Context paragraphs:
W. A. Cleveland: Waldo Atwood Cleveland (October 22, 1890 – August 25, 1952) was an agriculturist who was the head football coach for the Western Illinois University Leathernecks located in Macomb, Illinois and he held that position for two seasons, from 1920 until 1921.  His career coaching record at Western Illinois was 3 wins, 6 losses, and 2 ties.  This ranks him 17th at Western Illinois in total wins and 16th at Western Illinois in winning percentage.

Ray Hanson: Raymond W. "Rock" Hanson (October 5, 1895 – January 4, 1982), former United States Marine Colonel and highly decorated veteran of World War I and World War II, was best known as the football coach at Western Illinois State Teachers College (now Western Illinois University) in Macomb, Illinois from 1926 to 1941.

Commandant of the Marine Corps: The Commandant of the Marine Corps (CMC) is normally the highest-ranking officer in the United States Marine Corps and is a member of the Joint Chiefs of Staff.  The CMC reports directly to the United States Secretary of the Navy and is responsible for ensuring the organization, policy, plans, and programs for the Marine Corps as well as advising the President, the Secretary of Defense, the National Security Council, the Homeland Security Council, and the Secretary of the Navy on matters involving the Marine Corps.  Under the authority of the Secretary of the Navy, the CMC designates Marine personnel and resources to the commanders of Unified Combatant Commands.  The Commandant performs all other functions prescribed in Section 5043 in Title 10 of the United States Code or delegates those duties and responsibilities to other officers in his administration in his name.  As with the other joint chiefs, the Commandant is an administrative position and has no operational command authority over United States Marine Corps forces.

Howard Hawkes: Howard George Hawkes (October 28, 1894 – May 15, 1970) was the head football coach for the Western Illinois University Leathernecks located in Macomb, Illinois and he held that position for four seasons, from 1922 until 1925.  His career coaching record at Western Illinois was 14 wins, 15 losses, and 2 ties.  This ranks him 11th at Western Illinois in total wins and 11th at Western Illinois in winning percentage.  A native of Windham, Maine, Hawkes graduated from Windham High School in 1911.  He received his B.P.E. degree from International Y.M.C.A. College at Springfield, Massachusetts in 1923.

Francesco Maria Scala: Francesco Maria Scala (1819 – 18 April 1903) also known as Francis M. Scala, was an Italian-born naturalized American military band director and musician.  He was the first and one of the most important and influential directors of United States Marine Corps (USMC) Band.  He defined the instrumental organization that the band maintains, he was an extremely prolific musician and composer, and improved and enlarged the repertoire of the ensemble.  It is thought that under his direction the USMC Band executed for the first time the melody "Potpourri-Fantasie" from the opera Geneviève de Brabant by Jacques Offenbach.  This melody is now known as the Marines' Hymn.

3d Light Antiaircraft Missile Battalion: 3d Light Antiaircraft Missile Battalion (3d LAAM Bn) was a United States Marine Corps air defense unit equipped with the medium range surface-to-air MIM-23 HAWK Missile System.  During World War II, the battalion was known as the 3rd Defense Battalion and took part in combat operations at Pearl Harbor, Midway, Guadalcanal and Bougainville.  The unit was deactivated in late 1944 but was brought back into service as the Marine Corps began to transition to surface to air missiles for their air defense needs in the early 1950s.  During the mid to late 1950s, the battalion was based at Marine Corps Training Center 29 Palms, California and was one of two Marine Corps units that operated the land-based version of the RIM-2 Terrier Missile.  In January 1963 3d LAAM battalion was moved to Marine Corps Air Station Cherry Point, North Carolina and would eventually fall under the command of Marine Air Control Group 28 (MACG-28) and the 2nd Marine Aircraft Wing (2nd MAW).  3d LAAM Battalion's final combat tour saw it providing air defense for the Marine Corps area of operations during Operation Desert Shield/Desert Storm.  3d LAAM Battalion was deactivated on 30 September 1994 as part of the post-Cold War draw down of forces and because the Marine Corps had made the decision to divest itself of its medium-range air defense.

Western Illinois University: Western Illinois University (WIU) is a public university located in Macomb, Illinois, United States.  It was founded in 1899 as Western Illinois State Normal School.  Like many similar institutions of the time, Western Illinois State Normal School focused on teacher training for its relatively small body of students.  As the normal school grew, it became Western Illinois State Teachers College.

United States Marine Corps Recruit Training: United States Marine Corps Recruit Training (commonly known as "boot camp") is a 12-week program of initial training that each recruit must successfully complete in order to serve in the United States Marine Corps.  All enlisted individuals entering the Marine Corps, regardless of eventual active or reserve duty status, will undergo recruit training at one of the two Marine Corps Recruit Depots (MCRD): Parris Island, South Carolina, or San Diego, California.  Male recruits from the 8th, 9th and 12th recruiting districts (areas west of the Mississippi River except Louisiana, and including parts of Illinois, Indiana, Wisconsin and Michigan) are sent to MCRD San Diego.  All recruits from the 1st, 4th and 6th recruiting districts and all female recruits are sent to Parris Island.  Those desiring to become officers attend training at Officer Candidates School at Marine Corps Base Quantico in Virginia.

Whittington (opera): Whittington is an opera (described in the premiere programme as 'A New Grand Opera Bouffe Feerie, in Four Acts and Nine Tableaux) with music by Jacques Offenbach, based on the legend of "Dick Whittington and His Cat".  It was premiered in a spectacular production at the Alhambra Theatre, London, on 26 December 1874.  "Whittington" is the only major work of Offenbach to have received its premiere in London, and came between the incidental music for "La Haine" and his third version of "Geneviève de Brabant".

Marines' Hymn: The "Marines' Hymn" is the official hymn of the United States Marine Corps, introduced by the first Director of USMC Band, Francesco Maria Scala.  It is the oldest official song in the United States Armed Forces.  The "Marines' Hymn" is typically sung at the position of attention as a gesture of respect.  However, the third verse is also used as a toast during formal events, such as the birthday ball and other ceremonies.  Western Illinois University uses the hymn prior to all football games.  They are the only non-military academy allowed to use the hymn.  The university has had permission to use the official nickname, mascot, and hymn of the Corps since 1927.

Supporting paragraphs: Francesco Maria Scala Marines' Hymn
Answer: "Potpourri-Fantasie"