A survey by American police experts found that corpsmen usually came from the lower levels of village society, had scant education and received little or no training.

The experts estimated that "the capability of the SDC [Self-Defense Corps] to withstand assaults by armed and organized [VC] units is virtually null."

The advisory group believed that in most areas of the South the Self-Defense Corps was thoroughly infiltrated by the Communists; in some provinces it even reportedly "covers up more information than it furnishes".

[5]: 320–1 A static, part-time, militia force, the Self-Defense Corps was intended to protect villages "against the subversive activities of dissident elements.

"[5]: 321  The Corps was so notoriously ineffective and so heavily infiltrated by Communists that many members of the country team, including United States Ambassador to South Vietnam Elbridge Durbrow, favored dropping it entirely from the U.S. aid program.

Military Assistance Advisory Group (MAAG) commander General Samuel Tankersley Williams argued forcefully for U.S. support of a Self-Defense Corps of at least 43,500 men.

Subsequently the two were placed under the Joint General Staff (JGS) and given a single chain of command, but remained separate from the regular ARVN until 1970.

[6]: 43  The number of Popular Forces declined during 1965, with a net loss of 25,000 from casualties and desertions, leaving them with about 135,000 troops out of an authorized 185,000 at the end of the year.

[6]: 151–2  By June 1966 high desertion rates and recruiting shortfalls in the territorial components finally led Westmoreland to freeze the authorized force structure and to make drastic reductions in his projected increases.

[6]: 257 In March 1967 at Westmoreland's suggestion, JGS Chairman General Cao Văn Viên activated 333 more Popular Forces platoons.

The remaining territorial units were presumably either in the process of formation, in training, defending bases and installations, outposting roads, or conducting conventional combat operations.

[6]: 216  In late February 1968 in the wake of the Tet Offensive Westmoreland requested 268,000 M16 rifles and 11,200 M79 grenade launchers for the territorials, who with their Korean War era small arms were outgunned by the PAVN/VC.