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How the U.S. Marines Work

        Science | Branches

Marine Corps Structure
Commandant of the Marines
Photo courtesy of the U.S. Marines
Commandant of the Marine Corps, General James T. Conway
Although the Marine Corps is a separate branch of the U.S. military, it does not have its own department within the Department of Defense as the Army, Navy and Air Force do. The Marine Corps is part of the Department of the Navy. At an administrative, political and civilian level, the Marines operate beneath the Secretary of the Navy. However, the highest ranking Marine Corps officer, the Commandant of the Marine Corps, does not answer to any other military officer. He is the military head of the Corps. Every Marine Corps Commandant has lived in the Marine Barracks in Washington, D.C. It is the oldest official building in Washington that has remained in continuous use for its original purpose. [Source: Global Security]. The Marines pride themselves on efficiency, claiming to supply 20 percent of the U.S. armed forces’ combat power while using only 6.5 percent of the Department of Defense’s budget. [Source: Marines Magazine].

The Marines are divided into four separate groups:

  • Operating Forces – Do the actual fighting.
  • Headquarters Marine Corps (HQMC) – Upper echelons of Marine Corps leadership, based in Arlington, VA.
  • Supporting Establishment – Provides logistical support to Corps missions. This includes supplying ammo and food, medical facilities and communications equipment.
  • Marine Forces Reserve – Train one weekend per month and two weeks per year and can be called up when needed to support or replace Marines; ready reserves are Marines who have completed their active duty but may be recalled if needed.

Urban warfare training
Photo courtesy of the U.S. Marines/Photographer: Sgt. Jerad W. Alexander
Marines advance on a building during urban warfare training.
The Operating Forces are split between Marine Forces Pacific and Marine Forces Atlantic, with each force in charge of operations in their respective area. While the Corps is divided into Divisions, Regiments and Battalions, it is more meaningful to recognize that Marines are organized into Expeditionary Forces, Brigades and Units when they are sent to deal with a specific problem. The deployment of Marine units is not limited by a rigid organizational structure, allowing for each Expeditionary group to be tailored to a specific mission profile. For example, a mission in a heavily populated area will require troops suited for urban warfare, while missions into mountainous regions will not require many tanks. An Expeditionary group of any size brings everything it needs to get the job done, including the ground combat element (GCE) and an air combat element (ACE) for close air support and helicopter insertion. They will also have enough supplies for a minimum of two weeks – most have 60 days of supplies. This reflects a revision of doctrine after a debacle at Guadalcanal in World War II. Navy vessels dropped the Marines on the beach, but were driven back by Japanese fire before they could unload equipment and supplies. The Marines were forced to fight and survive using captured weapons and rice (Halberstadt, 21).

Storage unit
Photo courtesy of the U.S. Marines/Photographer: Lance Cpl. Brandon L. Roach
Lance Cpl. Jonathan W. Chaline tidies one of his storage units where supplies are stored at Al Asad, Iraq.
This combined arms strategy is central to the Marine Corps. While the other armed forces have to form a “unified command” to combine Air Force, Army and Navy operations, the Marines bring everything they need with them to get the mission done. While the Army has light infantry units capable of deploying more quickly than the Marines, they require reinforcement and resupply within a few days. A Marine Expeditionary Unit can arrive relatively quickly (obviously not as quickly as light infantry paratroopers) with all the armor, air support and supplies they need for an extended mission.

The Corps also places a heavy emphasis on decentralization of command. Junior officers are given greater responsibility and decision-making abilities than soldiers of the same rank in other armed forces. The general rule is: “Follow the spirit of an order (from higher ranking officers), even if you don’t follow the order to the letter.” In other words, if a Marine unit is ordered to get something done, the individual commander within that unit has the freedom to decide the best way to do it.

Marines vs. the Army
The Marine Corps has a long-standing rivalry with the U.S. Army. The Marines’ elitist attitude often grates on Army troops, who feel that the Marines duplicate the Army’s capabilities. The Marines, for their part, feel that they do a better job at their specific tasks and are crucial to U.S. military goals. In the wake of both World War II and the Vietnam War, there was a strong push in the Department of Defense to get rid of the Marines altogether and fold their capabilities entirely into the Army. However, there are quite a few retired Marines who have gone on to political careers. Their efforts to preserve the Marines as a force and as a tradition have made it unlikely that the Marine Corps will be disbanded in the near future.

Marine Corps Ranks and Abbreviations
Commissioned Officers Warrant Officers Enlisted
General (GEN) Commandant of the Marine Corps Chief Warrant Officer 5 (CWO5) Sergeant Major of the Marine Corps (SgtMajMC)
Lieutenant General (Lt. Gen) Chief Warrant Officer 4 (CWO4) Master Gunnery Sergeant (MGySgt)
Major General (Maj. Gen.) Chief Warrant Officer 3 (CWO3) Sergeant Major (SgtMaj)
Brigadier General (Brig. Gen) Chief Warrant Officer 2 (CWO2) First Sergeant (1st SG)
Colonel (COL) Warrant Officer 1 (WO) Master Sergeant (MSG)
Lieutenant Colonel - (Lt. Col.)   Gunnery Sergeant (GySgt)
Major (MAJ)   Staff Sergeant (Ssgt)
Captain (CPT)   Sergeant (Sgt)
First Lieutenant (1st LT)   Corporal (CPL)
Second Lieutenant (2nd LT)   Lance Corporal (LCpl)
    Private First Class (PFC)
    Private (PV)