The US Marine Corps maintains three active and one reserve combat divisions to meet its operational responsibility under the National Security Act of “Providing rapidly deployable forces for contingency missions in support of National strategy”. In addition to the reserve division, an air wing and a service support group are maintained in reserve. The organizational structure of the Marine Corps is similar to, but more flexible than that of the army.
When called upon to provide a combat force, the Marine Corps organizes an air/ground task force (MAGTF) made up of four components:
Command is a single headquarters that controls all activities of all components of the MAGTF.
The Ground Combat element can be as small as one infantry battalion or as large as several divisions. Ground combat can include artillery, armor, assault vehicles, reconnaissance and combat engineers,
Aviation Combat element can range from a reinforced helicopter squadron to one or more air wings. Aviation combat may include air support, assault support, air reconnaissance, anti-aircraft defences, Electronic warfare, and Command and Control groups.
Combat Service Support is configured to meet the needs of the particular mission and includes all logistic supply services, maintenance, engineering, transport and Medical functions.
MAGTFs can be organized into three basic combined arms configurations to meet the needs of a specific mission. These are:
• Marine Amphibious Units, containing between 1,800 to 4000 marines and sailors
• Marine Amphibious Brigades, having 8,000 to 118,000-plus marines and sailors;
• Marine Amphibious Forces (MAF) of 50,000 plus marines and sailors.
Marines can operate as independent units or as part of a larger joint task force. The Marine Corps combat capability is presently organized into three MAFs, two of which are stationed in the Pacific and one in the Atlantic.