As its name says, the Vietnam War took place mainly in Vietnam, the easternmost country on the Indochina Peninsula in Southeast Asia. At the beginning of the war, most of the fighting took place in the South where the Republic of Vietnam (RVN) regime backed by the United States defended itself against Viet Cong insurgencies backed by the Democratic Republic of Vietnam (DRV). However, as the war went on, it expanded to the North and even to Cambodia and Laos who shared their eastern borders with Vietnam.
In South Vietnam
In mid-1957, the Viet Cong began to increase their guerrilla operations against Saigon government. As most urban population was strongly anti-communist, the guerrilla war took place mainly in rural areas where Viet Cong conducted many acts of terrorism against local government targets. In addition, they especially focused on propaganda operations to gain support from South Vietnamese peasants. The war now became a battle of taking control of rural territories, village by village. At the end of 1960, Viet Cong formally established the National Liberation Front (NLF) to unite all anti-government activists in South Vietnam. Despite the lack of experience and competence, the NLF grew rapidly into a large underground organization with a web of subordinate and associated groups in most of villages all over South Vietnam.
In return, South Vietnamese government conducted the Strategic Hamlet Program, a pacification effort begun in 1961 in order to secure rural population from the Viet Cong’s influence. However, the program eventually failed in 1963 because of poor executions. By March 1964, the Viet Cong had controlled about 40% of South Vietnamese rural territories including 80% of Phuoc Tuy, 90% of Binh Duong, 90% of Kien Tuong, 90% of Kien Hoa, and 85% of An Xuyen.
Since 1965, the war gradually shifted from guerrilla to conventional war. The numbers of battles in battalion-size or larger increased quickly during 1965 and 1966. As villages were not suitable for conventional combats, most of the fightings in this period took place far away from populated areas. Many of them took place in Central Highland such as Battle of Ia Drang or Battle of Dak To. Others took place in areas near the Cambodian border such as Operation Junction City or Battle of Loc Ninh. In 1968, the Tet Offensive marked the first time when fierce battles occurred in urban areas. Many major cities such as Hue and Saigon became the battlefield in which Viet Cong and the NVA engaged with allied forces in regiment-size battles. Since then, urban areas became major targets of later offensives conducted by the NVA, such as the Easter Offensive and Spring Offensive in 1972 and 1975 respectively.
In North Vietnam
It was the U.S. intention to limit the ground war in South Vietnam. They did not want to have another Yalu Campaign in Vietnam*, hence put North Vietnam off-limits for major ground offensives. Instead, U.S. forces began to conducted many aerial operations to destroy North Vietnam’s infrastructures and halt the supply lines from the North into South Vietnam through the Ho Chi Minh trail.
In early 1965, Washington conducted Operation Rolling Thunder against North Vietnam. However, by adopting “gradualism” strategy, the U.S. was reluctant to permit attacks on critical targets near Hanoi and Haiphong. Instead, they mostly bombed less important targets in the southern of North Vietnam. In return, Hanoi rapidly set up a sophisticated air defense and inflicted heavy damage on U.S. air forces. By 1968, Operation Rolling Thunder was halted but none of its objectives were achieved effectively.
In late 1972, in order to bring Hanoi back to negotiation tables in Paris, Washington conducted another massive bombing operation called Linebacker II. Unlike most of previous air campaigns, many previous restrictions preventing U.S. aircrafts from bombing critical targets in Hanoi and Haiphong were removed in Linebacker II. Therefore, Operation Linebacker II was highly effective. During 11 days of bombing with a total of 20,237 tons of bombs were dropped, the air raids had significantly destroyed North Vietnam’s infrastructures and successfully forced Hanoi to resume the negotiations.
Cambodia and Laos
In early 1965, North Vietnamese began to use eastern areas of Cambodia and Laos as sanctuaries to conduct their military training and stock supplies. Moreover, they even built up the famous Ho Chi Minh Trail, a principal supply route from the North to the South, in these countries. For many years, U.S. military advisers and generals advocated military attacks against these enemy sanctuaries but they were all rejected by President Johnson due to political reasons.
However, after the Viet Cong launched some “Mini-Tet” Offensive of 1969 within South Vietnam, President Richard Nixon authorized a covert air campaign to bomb communist bases in eastern Cambodia in March 1969. Following the aerial campaign, the United States and South Vietnamese units continued to launch a series of ground and air operations in 1970 to eliminate the remaining North Vietnamese forces in eastern Cambodia. By combining their devastating air power and ground forces, the incursion achieved great success killing thousands of Viet Cong and capturing huge amount of communist supplies and materiel.
Following Cambodia, Laos became the next place where the allied forces conducted their operations. On February 8, 1971, ARVN forces began to conduct Operation Lam Son 719 in southeastern portion of Laos without U.S. forces and advisers. This operation was a test of Nixon’s Vietnamization policy whether ARVN could operate effectively by itself. A swift victory could bolster the morale of ARVN troops, which was already high in the wake of the successful Cambodian Incursion in 1970. However, ARVN units failed to prove themselves when facing strong resistance from a skillful foe. In fact, the campaign was a disaster for the South Vietnamese forces as they lost not only some of their best units but also the confidence they had built up over the previous three years.
(*) In Korean War, when the U.S. forces crossed the Yalu River located in the south of the border between North Korea and China, Beijing sent hundreds of thousands of troops into the war.