In 1965, President Lyndon Baines Johnson rapidly increased the American military presence in Southeast Asia. Meanwhile, the National Guard prepared at home for the possibility of mobilization.

On July 28, 1965, President Johnson announced his refusal to federalize National Guard units to augment the initial American buildup in Vietnam. As an alternative, the Department of Defense created the Select Reserve Force (SRF). The SRF consisted of selected Army National Guard and Army Reserve units to be maintained at a heightened state of readiness and to serve as a strategic reserve to offset the deployment of active-duty soldiers to Southeast Asia. The Army National Guard provided 120,000 of the 150,000 man force in three composite infantry divisions and six separate brigades. By July 1966, 88 percent of SRF National Guard units had passed a readiness test by demonstrating the ability to mobilize with 7 days for deployment and combat. Guardsmen rechristened the SRF as the “Super-Ready Force” to reflect the units’ rapid mobilization capability.

In August of 1965, the Secretary of Defense identified 14 “Air National Guard tactical units to be fully manned, equipped, and geared for instant mobilization.” Named the “Beef Broth” force, the program was the Air Guard’s implementation of the SRF, and by June 1966, the units were fully operational. The “Beef Broth” units, supplemented by additional tactical squadrons, assumed operational responsibility for air-ground support training from the Air Force’s Tactical Air Command. Meanwhile, the Air Guard continued to train with real-world support of current operations. Beginning in August 1965 and continuing until 1967, Air Guard units began flying aeromedical evacuation flights to and from Hawaii and Southeast Asia (primarily Japan and the Philippines). The flights picked up casualties evacuated from Republic of Vietnam by regular Air Force or Navy aircrews. Worldwide, the Air National Guard supported Air Force operations, and on average, Guardsmen flew 200 overseas flights per month in support of the Military Airlift Command’s global airlift operations.”