Vietnam War, military struggle fought in Vietnam from 1959 to 1975. It began as a determined attempt by Communist guerrillas (the so-called Vietcong) in the South, backed by Communist North Vietnam, to overthrow the government of South Vietnam. The struggle widened into a war between South Vietnam and North Vietnam and ultimately into a limited international conflict. The United States and some 40 other countries supported South Vietnam by supplying troops and munitions, and the USSR and the People’s Republic of China furnished munitions to North Vietnam and the Vietcong. On both sides, however, the burden of the war fell mainly on the civilians.
The war also engulfed Laos, where the Communist Pathet Lao fought the government from 1965 to 1973 and succeeded in abolishing the monarchy in 1975; and Cambodia, where the government surrendered in 1973 to the Communist Khmer Rouge.
This article is concerned primarily with the military aspects of the war; for further discussion of the historical and political issues involved, see Vietnam: History.
(1945-54). The war developed as a sequel to the struggle (1946-54) between the French, who were the rulers of Indochina before World War II, and the Communist-led Vietminh, or League for the Independence of Vietnam, founded and headed by the revolutionary leader Ho Chi Minh. Having emerged as the strongest of the nationalist groups that fought the Japanese occupation of French Indochina during World War II, the league was determined to resist the reestablishment of French colonial rule and to implement political and social changes.
Following the surrender of Japan to the Allies in August 1945, Vietminh guerrillas seized the capital city of Hanoi and forced the abdication of Emperor Bao Dai. On September 2 they declared Vietnam to be independent and announced the creation of the Democratic Republic of Vietnam, commonly called North Vietnam, with Ho Chi Minh as president. France officially recognized the new state, but the subsequent inability of the Vietminh and France to reach satisfactory political and economic agreements led to armed conflict beginning in December 1946. With French backing Bao Dai set up the state of Vietnam, commonly called South Vietnam, on July 1, 1949, and established a new capital at Saigon (now Ho Chi Minh City).
The following year, the U.S. officially recognized the Saigon government, and to assist it, U.S. President Harry S. Truman dispatched a military assistance advisory group to train South Vietnam in the use of U.S. weapons. In the meantime, the two main adversaries in Vietnam-France and the Vietminh-were steadily building up their forces. The decisive battle of the war developed in the spring of 1954 as the Vietminh attacked the French fortress of Dien Bien Phu in northern Vietnam. On May 8, 1954, after a 55-day siege, the French surrendered.
On the same day, both North and South Vietnamese delegates met with those of France, Great Britain, the Soviet Union, the United States, Communist China, and the two other Indochinese states, Laos and Cambodia, in Geneva, to discuss the future of all of Indochina. Under accords drawn up at the conference, France and North Vietnam agreed to a truce. It was further agreed to partition the country temporarily along the 17th parallel, with the north going to the Communists and the south placed under the control of the Saigon government. The agreement stipulated that elections for reunification of the country would be held in 1956.
Neither the U.S. nor the Saigon government agreed to the Geneva accords, but the U.S. announced it would do nothing to undermine the agreement. Once the French had withdrawn from Vietnam, the U.S. moved to bolster the Saigon government militarily and, as asserted by some observers, engaged in covert activities against the Hanoi government. On October 24, 1954, President Dwight D. Eisenhower offered South Vietnam direct economic aid, and the following February, U.S. military advisers were dispatched to train South Vietnamese forces. American support for the Saigon government continued even after Bao Dai was deposed, in a referendum on October 23, 1955, and South Vietnam was made a republic, with Ngo Dinh Diem as president. One of Diem’s first acts was to announce that his government would refuse to hold reunification elections, on the grounds that the people of North Vietnam would not be free to express their will and because of the probability of falsified votes (although Diem and other South Vietnamese officials were also accused of fraudulent election practices).