North Vietnam announces the formation of the National Front for the Liberation of the South at a conference held "somewhere in the South." This organization, more commonly known as the National Liberation Front (NLF), was designed to replicate the success of the Viet Minh, the umbrella nationalist organization that successfully liberated Vietnam from French colonial rule.
The NLF reached out to those parts of South Vietnamese society who were displeased with the government and policies of President Ngo Dinh Diem. One hundred delegates representing more than a dozen political parties and religious groups--both communists and non-communists--were in attendance at the conference. However, from the beginning, the NLF was dominated by the Lao Dong Party Central Committee (North Vietnamese Communist Party) and served as the North's shadow government in South Vietnam. The Saigon regime dubbed the NLF the "Viet Cong," a pejorative contraction of Viet Nam Cong San (Vietnamese Communists).
The NLF's military arm was the People's Liberation Armed Forces (PLAF). In February 1965, the PLAF attacked U.S. Army installations at Pleiku and Qui Nhon, which convinced President Lyndon B. Johnson to send the first U.S. ground troops to South Vietnam a month later. Ultimately, more than 500,000 U.S. troops were sent to Vietnam to fight the PLAF and the People's Army of Vietnam (PAVN, or North Vietnamese Army).
The NLF reached the height of its power during the 1968 Tet Offensive, when the communists launched a massive coordinated attack against key urban centers throughout South Vietnam. Although the Viet Cong forces were soundly defeated during the course of the offensive, they achieved a great psychological victory because the attack prompted many long time supporters of the war to question the Johnson administration's optimistic predictions.