The Marine Corps Reserve, established by the Naval Appropriations Act (1916), provided for the wartime expansion of the Corps without changing its statutory regular strength. The initial legislation focused on establishing the mobilization status of individuals, not units. In World War I, 7,500 Marines (including 277 women) were reservists.

Aware that its war plans required two to three times as many Marines as it could maintain on active duty, Headquarters Marine Corps gave its reserve program greater attention in the interwar period, especially training junior officers. Of the 600,000 men and women who served in the Marine Corps in World War II, about two‐thirds fell into some reserve category that provided for the service of retirees, wartime volunteers and draftees, college students, volunteers below draft age, specialists, limited service personnel, and women.

The Cold War military establishment required a higher level of reserve training readiness as well as more reservists. The Reserve Forces Act (1948) finally provided regularized pay for drills and active duty training as well as a retirement system. The Marine Corps divided its members into an Organized Marine Corps Reserve (OMCR) (drill pay units); Volunteer Training Units (no pay, but retirement credit points); and the Volunteer Reserve (a pool of veterans with no training obligations, but some active duty training opportunities). The last group became known as the Individual Ready Reserve (IRR). In 1950, the Marine Corps Reserve numbered almost 40,000 members of the OMCR and 88,000 members in other categories. Over 95 percent of these Marines came on active duty during the Korean War.

Reserve reform acts in 1952, 1955, and 1957 did much to improve the preactivation readiness of Marine reserves. The most important provision (1955) was that all Marine reservists complete at least six months of initial active duty training before joining an Organized Marine Corps Reserve unit. The requirements for reserve officers were even more stringent—two or more years of active duty. The requirements for training increased. Summer camps expanded to two weeks, and drills shifted from one night a week to one or more weekends a month. The Ready Reservists numbered around 45,000 in drill pay units and 80,000 in the Individual Ready Reserve.

In the early 1960s, the Organized (or Select) Marine Corps Reserve became a regular part of the Fleet Marine Force: the 4th Marine Division, the 4th Marine Aircraft Wing, and the 4th Force Service Support Group. Unlike the army, the active duty Marine Corps (around 190,000 before and after the Vietnam War) remained four times as large as the organized reserves. Marine Corps reserve units did not mobilize for the war, but countless thousands of reservists volunteered as individuals for active duty in Southeast Asia.

After a troubled transition to an All‐Volunteer Force system in the 1970s, the Marine Corps Reserve rebuilt itself into a force of 40,000 members of the Select Reserve and 68,000 members of the Individual Ready Reserve. Around 28,000 members of this force came on active duty by volunteering or by federal activation to serve in the Persian Gulf War (1991). Operation Desert Storm showed that the policy of extensive active duty training and a generous commitment of regulars and full‐time reservists to reserve training and administration paid dividends in readiness.
[See also Marine Corps, U.S.; Marine Corps Women's Reserve; ROTC.]

Bibliography

Public Affairs Unit 4‐1, USMCR , The Marine Corps Reserve: A History, 1966.
Allan R. Millet , Semper Fidelis: The History of the United States Marine Corps, 1980; rev. ed. 1991.

Allan R. Millett