The Communist-held Democratic Republic of Vietnam was opposed by the US-supported Republic of Vietnam. Disagreements emerged over the organizing of elections and reunification, and the U.S. began increasing its contribution of military advisers. U.S. forces were soon embroiled in a guerrilla war with the National Front for the Liberation of South Vietnam (NLF), the insurgents who were indigenous to South Vietnam. North Vietnamese forces unsuccessfully attempted to overrun the South during the 1968 Tet Offensive and the war soon spread into neighboring Laos and Cambodia, in both of which the United States bombed Communist forces supplying the North Vietnamese Army.
In June 1964, General William C. Westmoreland became deputy commander of Military Assistance Command, Vietnam (MACV), assuming command from General Paul D. Harkins. As the head of the MACV he was known for highly publicized, positive assessments of US military prospects in Vietnam. However, as time went on, the strengthening of North Vietnamese combat forces in the South led to regular requests for increases in US troop strength, from 16,000 when he arrived to its peak of 535,000 in 1968 when he was promoted to Army Chief of Staff.
Under Westmoreland’s leadership, the United States “won every battle until it lost the war.”[2] The turning point of the war was the 1968 Tet Offensive, in which Communist forces, having baited Westmoreland into committing nearly 40% of his strength to Khe Sanh[citation needed], attacked cities and towns throughout South Vietnam. US and South Vietnamese troops successfully fought off the attacks, and the Communist forces took heavy losses, but the NVA General Vo Nguyen Giap orchestrated negative media coverage[citation needed] shook public confidence in Westmoreland’s previous assurances about the state of the war. Political debate and public opinion led the Johnson administration to limit further increases in US troops in Vietnam.
Westmoreland was convinced that the Vietnamese communists could be destroyed by fighting a war of attrition that, theoretically, would render the Viet Cong and the North Vietnamese unable to fight. His war strategy was marked by heavy use of artillery and airpower and repeated attempts to engage the communists in large-unit battles. However, the NVA and the Viet Cong were able to dictate the pace of attrition to fit their own goals: by continuing to fight a guerrilla war and avoiding large-unit battles, they denied the Americans the chance to fight the kind of war they were best at, and they ensured that attrition would wear the Americans faster than it would wear down the NVA and Viet Cong.
With its own casualties mounting, the U.S. began transferring combat roles to the South Vietnamese military in a process the U.S. called Vietnamization. The effort had mixed results. The Paris Peace Accords of January 27, 1973, formally recognized the sovereignty of both sides. Under the terms of the accords all American combat troops were withdrawn by March 29, 1973. Limited fighting continued, but all major fighting ended until the North once again sent troops to the South during the Spring of 1975, culminating in the Fall of Saigon on April 30, 1975. South Vietnam briefly became the Republic of South Vietnam, under military occupation by North Vietnam, before being officially integrated with the North under communist rule as the Socialist Republic of Vietnam on July 2, 1976.
Upon taking control, the Vietnamese communists banned all other political parties, arrested public servants and military personnel of the Republic of Vietnam and sent them to reeducation camps. The government also embarked on a mass campaign of collectivization of farms and factories. Reconstruction of the war-ravaged country was slow, and serious humanitarian and economic problems confronted the communist regime. Millions of people fled the country in crudely-built boats, creating an international humanitarian crisis. In 1978, the Vietnamese army invaded Cambodia (sparking the Cambodian-Vietnamese War) to remove the Khmer Rouge from power. This action worsened relations with China, which launched a brief incursion into northern Vietnam (the Sino-Vietnamese War) in 1979. This conflict caused Vietnam to rely even more heavily on Soviet economic and military aid.