Members of the People's Self-Defense Force of Kien Dien, in Bến Cát district.
During the Vietnam War, the South Vietnamese Popular Force (nghĩa quân) (sometimes abbreviated PFPF or PF) consisted of local militias that protected their home villages from attacks by first Viet Cong forces and later by People's Army of Vietnam units. Originally called the Civil Guard and the Self-Defense Corps, they were integrated into the Army of the Republic of Vietnam in 1964 and placed under the command of the Joint General Staff. The Popular Force was one of two broad groups of militia, the other being the Regional Forces (địa phương quân). The American forces referred to both groups as "Ruff-Puffs" referring to the abbreviation RFPF.
From 1965-1969, the ARVN took over most security operations as the Americans and other allies fought the main force war against the PAVN and NLF. When U.S. forces began to withdraw in 1969, the ARVN took on the task of fighting the communists, the Regional Forces and Popular Forces took on new importance. For the first time, they were deployed outside their home areas and were sometimes attached to ARVN units.
By 1973 the Popular forces consisted of 8,186 platoons. Charged primarily with local defense, they were too lightly armed and equipped to withstand attacks by PAVN units supported by tanks and artillery. They were overwhelmed during the 1975 Spring Offensive and dissolved.