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American Involvement in Vietnam, 1955–75

Exam code: 2147
Written by: Ashika|Reviewed by: Caroline Carroll|Updated 2 July 2026

Why did the USA get Involved in Vietnam?

Why Did the USA get Involved in Vietnam?

A map of Southeast Asia showing the division of Vietnam at the 17th Parallel. North Vietnam is shaded red and located above the 17th Parallel, with the capital area near the Gulf of Tonkin. South Vietnam is shaded blue and lies below the 17th Parallel, bordering the South China Sea. Surrounding countries are also labeled: China to the north, Laos and Cambodia to the west, Thailand and Myanmar to the southwest. The Gulf of Tonkin lies to the northeast of Vietnam, while the Gulf of Thailand is to the southwest. The 17th Parallel is marked with a dashed horizontal line across the map
A map showing how Vietnam was divided in 1954

  • Before the Second World War, France owned Vietnam

    • Vietnam was a colony in the French Empire known as Indochina

  • During the Second World War, Japan occupied Vietnam

    • In 1941, a Communist armed force called the Viet Minh under the leadership of Ho Chi Minh fought the Japanese

    • In 1945, Vietnam declared independence

  • After the Second World War, France wanted to own Vietnam again

    • France fought the Viet Minh

    • Fearing Communism in Vietnam, the USA funded the French involvement

  • The Viet Minh defeated the French at the Battle of Dien Bien Phu in 1954

    • The Geneva Peace Accords agreed to temporarily split Vietnam

      • The Communist Viet Minh gained North Vietnam

      • South Vietnam created an anti-Communist government

      • A free election in 1956 would decide who permanently governed Vietnam

A visual comparison of North Vietnam and South Vietnam’s leadership during the Vietnam War. On the left, North Vietnam is represented by Ho Chi Minh, labeled as "respected" and "known as 'Uncle Ho'," and is backed by the Soviet Union (flag shown). On the right, South Vietnam is represented by Ngo Dinh Diem, who is labeled as "unpopular," "corrupt, he rigged elections," and "Catholic, he persecuted Buddhists." Diem is backed by the United States (flag shown). The image uses red for communist North Vietnam and blue for capitalist South Vietnam.
An illustration showing key information about the leaders of North and South Vietnam

Reason

Why did this cause US intervention in Vietnam?

Domino Theory

Eisenhower and his Secretary of State John Dulles feared that Ho Chi Minh would win the election. This would make Vietnam Communist. They believed that if Vietnam turned Communist, other countries in Southeast Asia would fall too

Containment

Presidents Eisenhower, Kennedy and Johnson all believed in containment. They justified their actions in Vietnam as part of their mission to stop the spread of Communism

Distrust of the USSR and China

The USA blamed the USSR and China for North Vietnam’s attempt to spread Communism

Raw materials

Vietnam had a wealth of useful raw materials like tungsten, tin and rubber. If the USA could make Vietnam capitalist, it could access these raw materials

The Development of War in Vietnam

The Development of War in Vietnam

  • In 1957, the communist guerrillas (later known as the Viet Cong) began attacking South Vietnam

  • In 1959, the People's Army of Vietnam (PAVN) - popularly known as the North Vietnam Army (NVA) established the Ho Chi Minh Trail to transport weapons to the South

  • Ho Chi Minh declared a full-scale war against the Army of the Republic of Vietnam (ARVN)

    • He stated his intention to overthrow Diem’s government

  • Many South Vietnamese supported the actions of North Vietnam

    • In 1960, Ho Chi Minh created the National Liberation Front (or the Vietcong) 

      • Its members included Communists from North Vietnam and peasants from South Vietnam

      • In reaction, President Kennedy sent more aid to support Diem’s government

  • Diem’s government became more unpopular

    • Diem introduced the Strategic Hamlets programme in 1962

      • It aimed to create villages protected from the Viet Cong’s influence

      • In reality, it destroyed people’s homes and forced them to move. This gained support for the Viet Cong

    • He treated his people poorly by:

      • Discriminating against Buddhists, the largest faith group in South Vietnam

      • Taking land from peasants to give to rich landlords

      • Running a corrupt government and giving key positions to his family members

  • The USA could no longer support Diem’s government

    • Kennedy cut off aid to Diem

    • In November 1963, a coup overthrew and assassinated Diem

The Events of the Vietnam War

The Events of the Vietnam War

A vertical timeline chart showing seven key events in the Vietnam War from 1964 to 1973. Each event is shown in a coloured box, numbered from 1 to 7, with arrows connecting them in chronological order. August 1964 (orange box): The USA accuses North Vietnam of attacking two US ships in the Gulf of Tonkin. This incident prompts US Congress to authorise military action in Vietnam. March 1965 (light green box): Operation Rolling Thunder begins — a large-scale US bombing campaign against North Vietnam. By the end of 1965, 20,000 US troops are in Vietnam. January 1968 (purple box): The Tet Offensive begins. North Vietnam launches surprise attacks on over 100 towns and cities. US and ARVN counter-attacks kill 30,000–50,000 North Vietnamese. March 1968 (yellow box): The My Lai Massacre. Lieutenant William Calley leads a US attack on a village suspected of hiding Viet Cong. Over 400 civilians are raped and killed. The US government covers it up for a year. 1969–1971 (pink box): President Nixon authorises bombing of Laos and Cambodia to improve the USA’s negotiating position in peace talks. March 1972 (orange box): North Vietnam, Laos and Cambodia launch the Easter Offensive — a major attack on South Vietnam in response to US bombings. January 1973 (blue box): The Paris Peace Accords are signed by the USA, North Vietnam, South Vietnam and the Viet Cong. All US troops are to withdraw from Vietnam by 1975.
A flow diagram showing the key events of US involvement in the Vietnam War, 1964-1973

Vietcong Tactics

Vietcong Tactics

Tactic

Explanation of tactic

Guerrilla warfare

The Viet Cong knew that the US would win in open warfare. Instead, the Viet Cong:

  • Set traps

  • Ambushed soldiers

  • Used Vietnam’s forests to attack and hide

  • Dug tunnels

The USA struggled to fight against these tactics

Use of civilians

Many South Vietnamese citizens helped the Viet Cong. They attacked South Vietnamese government officials. The Viet Cong did not wear a military uniform. As a result, US soldiers struggled to identify troops from civilians

Ho Chi Minh Trail

The North Vietnamese used the Ho Chi Minh Trail to transport supplies. Despite constant US bombing, supplies continued to move southwards on this route

A map showing the Ho Chi Minh Trail during the Vietnam War. The map displays North Vietnam (in red), South Vietnam (in blue), Laos, Cambodia, and parts of neighboring countries. Red arrows represent the Ho Chi Minh Trail—a supply route used by North Vietnam to transport troops and supplies into South Vietnam through Laos and Cambodia. Several arrows point toward key cities and regions in South Vietnam, including Hue, Kontum, Pleiku, Buon Brieng, Bu Prang, and Saigon. Blue dots mark U.S. Special Forces camps throughout South Vietnam. The 17th Parallel, which divided North and South Vietnam, is also labeled. The map includes key geographical features such as the Gulf of Tonkin, South China Sea, and Gulf of Thailand.
A map showing the Ho Chi Minh Trail

US Tactics

 US Tactics

Tactic

Explanation of tactic

Bombing

The US undertook large-scale bombing campaigns on North Vietnam’s capital city, Hanoi, key military bases and the Ho Chi Minh Trail. During the war, the USA dropped three million tonnes of bombs

Chemical warfare

The USA had a huge technological advantage over the North Vietnamese. They used chemicals like Napalm and Agent Orange. The aim was to destroy the dense forest that the Viet Cong hid in. This type of warfare caused high civilian casualties

Conscription

From 1967, the US government introduced conscription (or ‘the draft’). A large proportion of the US Army were young and Black Americans. Most of these soldiers had no choice but to fight in Vietnam. This meant that the US soldiers had low morale and wanted to return to the USA

Search and Destroy

The US sent troops in helicopters to find and attack Viet Cong bases. This method caused many deaths. Viet Cong traps killed US soldiers. US troops attacked innocent villagers in the belief they were Viet Cong. Search and Destroy pushed many Vietnamese to support the Viet Cong

Why did Public Opinion Turn Against the Vietnam War?

Why Did Public Opinion Turn Against the Vietnam War?

  • The US public turned against the Vietnam War because:

    • Conscription was unpopular

      • Around 2.8 million US soldiers fought in Vietnam

      • The draft affected black Americans disproportionately

      • The police prosecuted over 9,000 young men for ‘draft dodging’ 

    • The Tet Offensive (1968) caused the media to question if the war was worthwhile

    • It was the first televised war

      • The US public saw photographs and news reports of the Vietnam War in graphic detail

      • Scandals like the My Lai Massacre were uncovered, changing the public’s perception of the US Army

  • Anti-war protests peaked 1968-70

    • Students were the key opposition group to the war

      • In November 1969, 700,000 anti-war protesters marched in Washington

      • In May 1970, the National Guard shot dead four student protestors at Kent State University

      • The media coverage of the shootings caused 2 million students in 400 schools to go on strike

Protesters holding signs advocate for peace and ending the Vietnam War, walking on a sidewalk with a background of trees and buildings.
A picture of a student protest at the University of Wisconsin-Madison, January 1965
A man and woman sit in a living room watching a vintage television. The man holds newspapers. The TV shows a black-and-white scene.
A photograph showing an American man and woman watching footage of the Vietnam War on a television in their living room in 1968

The Consequences of the end of the Vietnam War

The Consequences of the End of the Vietnam War

  • President Nixon won the 1968 presidential election on the promise to end the Vietnam War

    • Nixon and his National Security Adviser, Henry Kissinger, wanted to pull out of the war with dignity

  • After the unsuccessful bombing campaigns of Laos and Cambodia, Nixon began the process of US withdrawal

    • In January 1973, the US and the North Vietnamese government signed the Paris Peace Accords

      • This officially ended US involvement in Vietnam

      • Nixon declared the US withdrawal was ‘peace with honour’

    • By 1973, only 30,000 US troops remained in Vietnam

      • The conflict between North and South Vietnam continued

    • On 30th April 1975, the South Vietnamese capital, Saigon, fell to North Vietnamese forces

Positive consequences

Negative consequences

The US public was happy to see the end of the ‘unwinnable war’

Containment had failed militarily. While the USA had stronger weapons, the communist Viet Cong had better tactics

Containment had failed politically. By 1975, Vietnam, Laos and Cambodia became Communist. The USSR and China, who had given money and technology to North Vietnam, had gained new Communist allies

Containment had failed in the propaganda war. The use of chemical warfare and disregard for Vietnamese civilians ruined the USA’s international reputation. Over 58,000 US soldiers died with millions of Vietnamese casualties

Containment had failed economically. The Vietnam War cost the USA around $168 billion

  • As a result, the US government abandoned the policy of containment

    • Nixon pursued détente with the USSR and China

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