The Marine Security Guard (MSG) Program, in its current form, has been in place since December 1948, but the Marine Corps has a long history of cooperation and distinction with the Department of State (DOS) going back to the early days of the Nation. From the raising of the United States flag at Derna, Tripoli, and the secret mission of Archibald Gillespie in California, to the 55-days at Peking, the United States Marines have served many times on special missions as couriers, guards for embassies and delegations, and to protect American officials in unsettled areas.
The origins of the modern MSG Program began with the Foreign Service Act of 1946 that stated the Secretary of Navy is authorized, upon the request of the Secretary of State, to assign enlisted Marines to serve as custodians under the supervision of the senior diplomatic officer at an embassy, legation, or consulate. Using this Act, the DOS and U.S. Marine Corps entered into negotiations to establish the governing provisions for assigning MSGs overseas. These negotiations culminated in the first joint Memorandum of Agreement signed on 15 December 1948. Trained at the DOS's Foreign Service Institute, the first MSGs departed for Tangier and Bangkok on 28 January 1949. The authority granted in the Foreign Service Act of 1946 has since been replaced by Title 10, United States Code 5983, and the most recent Memorandum of Agreement was signed on 13 March 2008. The Marine Corps assumed the primary training responsibility of its MSGs during November 1954.
MCESG is a tenant organization located in Marshall Hall, Marine Corps Base, Quantico, Virginia and is responsible to the Deputy Commandant, Plans, Policies and Operations, Headquarters, U.S. Marine Corps. Specially screened Marines assigned to MCESG are trained at the Marine Security Guard School and processed for duty overseas under the operational control of the DOS as MSGs. These Marines currently serve at 148 embassies and consulates around the world. MCESG also coordinates the personnel assignment, provides logistics support, and ensures threat related training of the Marines is kept up-to-date for mission accomplishment and currency.
MCESG's mission is to exercise command, less operational control of the MSG's, in that it is responsible for their training, assignment, administration, logistics support, and discipline. Regional Commanders provide operational oversight through the use of semi-annual inspections and command visits. The MSGs' primary mission is to provide internal security services at designated U.S. Diplomatic and Consular facilities to prevent the compromise of classified information and equipment that is vital to national security of the United States of America. The secondary mission of the MSG is to provide protection for U.S. citizens and U.S. Government property located within designated U.S. Diplomatic and Consular premises/facilities during exigent circumstances that require immediate aid or action.