The National Front for the Liberation of South Vietnam (NLF) was a political movement in South Vietnam, dominated by North Vietnamese, in opposition to the Republic of Vietnam. Its military arm was the Viet Cong.
It was dominated by Communists, but certainly took advantage of nonaligned opponents. During the Ngo Dinh Diem government, and especially during the Buddhist crisis, such opponents cautiously affiliated. Other groups, such as the Cao Dai and Hoa Hao, tried not to affiliate with anyone.
Many of the original Viet Cong were dead by the time the People's Army of Viet Nam took control of the South in 1975; losses were especially heavy during the 1968 Tet Offensive.