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Tip of the Spear: The 13 Missions for the U.S. Marines in Okinawa

Marines from the 31st MEU aboard the USS Essex. Images from, U.S. Navy, and

The latest from the Project 2049 Institute’s Insight Series

By: Tetsuo Kotani |

The shifting balance of military power in the Asia-Pacific is altering strategic calculations as the region faces a range of potential security contingencies. In the vast Asia-Pacific maritime theater, naval and air power can offer decisive advantages. Yet, the increasingly complex spectrum of possible contingencies, ranging from military confrontation to disaster relief, calls for retention of flexible response options. As the U.S. Air Force and Navy move toward an AirSea battle concept to preserve power-projection in the face of challenges, including China’s growing anti-access/area-denial (A2/AD) capabilities, the U.S. Marines on Okinawa remain a potent “tip of the spear” with their unique ability to operate from the sea as an integrated expeditionary air-ground force.

This integrated force, known as the Marine Air Ground Task Force (MAGTF), unites air, ground and logistics elements under a single command element for both autonomous and joint operations. Its flexibility and versatility distinguishes the MAGTF as the premier global emergency response force.

MAGTF is unique among the militaries of the world because of its scalability in size, capability and capacity in meeting a growing requirement or threat. It can be arranged in formations according to demand of the mission, ranging from a formidable Marine Expeditionary Force (MEF) to a smaller Marine Expeditionary Brigade (MEB) or an even more nimble Marine Expeditionary Unit (MEU). The MAGTF is usually deployed from the sea and the required logistics to self-sustain operations ashore increases with the size of the MAGTF.

The MEF is the largest MAGTF, numbering 20,000 to 90,000 Marines, and the principle Marine war fighting organization; capable of both amphibious and sustained operations ashore. A MEF provides geographic combatant commanders with a rapid response force capable of conducting conventional amphibious and maritime operations across a spectrum of visibility and weather conditions, deploying from the sea, by surface and/or by air under communications and electronics restrictions. The III MEF is based in Okinawa and is forward deployed to respond to larger crises or contingencies, such as combat operations on the Korean peninsula or in the defense of Japan as accorded by the Treaty of Mutual Security and Cooperation.

Marines from the 31st MEU aboard the USS Essex

The MEF formation also ensures the combatant commander has MEF or MEB sized force for sustained combat operations as well as a MEU sized force for smaller scale rapid response. The MEB is a mid-sized MAGTF consisting of up to 20,000 Marines and is equipped with amphibious assault capabilities and capacity to sustain operations ashore for approximately 30 days.

The smallest MAGTF, the MEU, consists of 1,500 to 3,000 Marines. MEUs are forward deployed around the world with the 31st MEU based in Okinawa. The 31st MEU also maintains a sea-based forward presence onboard the U.S. Navy’s “Task Force 76” (Amphibious Force, Seventh Fleet) vessels, based out of Sasebo, Nagasaki. In certain power-projection scenarios, the 31st MEU can be designated “Task Force 79” (Landing Force, Seventh Fleet), providing indispensable support to the Seventh Fleet.

The 13 primary unclassified missions of the 31st MEU are as follows:

Traditional Amphibious Missions

(1) Amphibious Assault

–The principal type of amphibious operation that involves establishing a force on a hostile or potentially hostile shore

(2) Amphibious Raid

–A type of amphibious operation involving swift incursion or temporary occupation of an objective followed by a planned withdrawal

(3) Maritime Interception Operations

–An amphibious operation including visit, board, search and seizure of a static maritime platform and selected maritime security missions.

(4) Advance Force Operations

–An amphibious operation to shape the battlespace in preparation for the main assault or other operations of an amphibious or Joint Force by providing battle space awareness and conducting reconnaissance, seizure of positions, preliminary bombardment and air support.

Expeditionary Support To Other Operations, Crisis Response And Limited Contingency Operations

(5) Tactical Recovery of Aircraft and Personnel (TRAP)

–Rescue or extraction of downed aircraft and personnel, aircraft sanitization, and provide advanced trauma-life support in a benign or hostile environment.

(6) Airfield/Port Seizure

–Secure an airfield, port, or other key facilities in order to support MAGTF missions or receive follow-on forces.

(7) Expeditionary Airfield Operations

–The capability to conduct tactical air operations at austere locations, including short-field, unimproved runways.

(8) Stability Operations

–Conduct operations to help establish order when civilians cannot do so, to secure a lasting peace and facilitate withdrawal of U.S. troops.

Non-Combat Support Missions during Peacetime and Crisis

The 31st MEU respond after Indonesian earthquake

(9) Humanitarian Assistance/Disaster Relief

–Programs conducted to relieve/reduce the results of natural or manmade disasters or other endemic conditions that might present a serious threat to life or that can result in great damage to or loss of property.

(10) Theater Security Cooperation

— Conduct combined and multinational military non-combat activities with other nations within the theater to advance mutual defense and security arrangements and to build allied and friendly military capabilities for self-defense and multinational operations.

(11) Non-combatant Evacuation Operations (NEO)

–Operations directed by U.S. government whereby noncombatants are evacuated from foreign countries when their lives are endangered to safe havens or to the United States.

MEU Special Operations Capable MEU-SOC

(12) Direct Action

–Short duration strikes and other small-scale offensive actions in hostile, denied or politically sensitive environments against designated targets.

(13) Special Reconnaissance

–Surveillance in hostile, denied or politically sensitive areas to collect or verify information of strategic or operational significance.

The 31st MEU is capable of quick reaction both in crisis and peacetime—rapidly assembling required forces to accomplish missions, using intelligence-based operational decision making, and acting as a rapid response force. In peacetime, the MEU acts as a “goodwill ambassador” and engages in stability operations (Mission 8), humanitarian assistance and disaster relief (Mission 9), and theater security cooperation (Mission 10).

In the future, the 31st MEU will likely be called into action in a number of imaginable contingencies in northeast Asia due to its range of capabilities. In addition to conventional amphibious operations (Missions 1 and 2), the MEU has the capability to accomplish maritime interception operations (Mission 3), shape the battlespace in advance of follow-on forces (Mission 4), and conduct non-combatant evacuation (Mission 11).

In the event of a military scenario on the Korean Peninsula or in the Taiwan Strait, the MEU can enable the full combat capabilities of the MEF for sustained operations. In the event of a regime collapse in Pyongyang, the 31st MEU can search and seize North Korean nuclear arsenal and prevent proliferation of those weapons (Mission 11). Although tensions across the Taiwan Strait have reduced, the 31st MEU can still play an important role by creating a fait accompli that the United States would be involved in any Chinese attack on Taiwan (Mission 4). Secretary Clinton’s recent assurance that the contested Senkaku Islands are subjected to the bilateral security treaty also places emphasis on the United States’ ability to respond in the event of an armed attack on Japan.

Amphibious assault vehicle assigned to 31st MEU

The 31st MEU will continue to play an important role even as the U.S. places an increasing emphasis on the AirSea battle. While the concept aims to limit damage to U.S. forward bases and forces while maintaining command and control networks and operational logistics, the MEU can act as the advance force (Mission 4) to provide tactical air power support under the A2/AD environment in support of U.S. Air Force and Navy operations (Missions 5, 6 and 7). Additionally Marine special forces can conduct disrupting direct action activities (Mission 12) and special reconnaissance (Mission 13) in preparation.

Moreover, the combat capability of the U.S Marines is also a valuable psychological deterrent. The III MEF forces in the Western Pacific and the 31st MEU’s presence in Okinawa and Iwakuni sends a strong signal to potential aggressors that hostile actions against Japan could directly involve the United States. This “trip wire” effect afforded by the presence of U.S. Marine Corps on Okinawa also has significant implications for regional security beyond the U.S. – Japan security relationship, and any discussion on Okinawa should not miss this fact.

*The author thanks Mr. John Niemeyer and Ms. Noriko Niijima at Commander, U.S. Naval Forces, Japan (CNFJ) and anonymous staff at the Commander, U.S. Marine Corps Forces, Pacific for listing the13 primary MEU missions.

An alternate version of this article was published by Pacific Forum CSIS. 

Mr. Tetsuo Kotani is a special research fellow at the Okazaki Institute in Tokyo. He is also a member of the Project 2049 Institute International Advisory Council, a senior research fellow at the Research Institute for Peace and Security (RIPS), and a Pacific Forum CSIS Nonresident SPF Fellow.