Civilian Irregular Defense Group program (CIDG, pronounced "sid-gee") was a program developed by the U.S. government in the Vietnam War to develop South Vietnamese irregular military units from minority populations.
The Civilian Irregular Defense Group program was formed for two reasons:
The CIDG program was devised by the CIA in early 1961 to counter expanding Viet Cong influence in South Vietnam's Central Highlands. Beginning in the village of Buon Enao, small A Teams from the U.S. Army Special Forces (Green Berets) moved into villages and set up Area Development Centers. Focusing on local defense and civic action, the Special Forces teams did the majority of the training. Villagers were trained and armed for village defense for two weeks, while localized Strike Forces would receive better training and weapons and served as a quick reaction force to react to Viet Cong attacks. The vast majority of the CIDG camps were initially manned by inhabitants of ethnic minority regions in the country (especially Montagnard), who disliked both the North and South Vietnamese and therefore quickly took to the American advisers. The program was widely successful, as once one village was pacified, it served as a training camp for other local villages.
By 1963, the military felt that the program was a great success, but also that the CIDG units and Special Forces units were not being employed properly, and ordered Operation Switchback, which transferred control of the CIDG program from the CIA over to Military Assistance Command, Vietnam. The CIDG Program was rapidly expanded, as the entire 5th Special Forces Group, U.S. Army Special Forces, moved into Vietnam, and the CIDG units stopped focusing on village defense and instead took part in more conventional operations, most notably border surveillance. Most of these were converted to Vietnam Army Ranger units in 1970.