Escalation of the Vietnam War

By the summer of 1964 the American commitment to South Vietnam had reached a decisive point. The Gulf of Tonkin Resolution of 7 August 1964 had given President Lyndon B. Johnson an open-ended authority to use force in Southeast Asia, and the Saigon government — a succession of military juntas following the assassination of Ngo Dinh Diem in November 1963 — was manifestly failing to hold the countryside against the Viet Cong. Over the next three years the United States transformed what had been an advisory mission into a large-scale conventional war, moving from Operation Rolling Thunder in March 1965 to a deployment of more than 485,000 troops by the end of 1967. The Tet Offensive of January 1968 would then mark the moment at which American public opinion turned decisively against that war.

This lesson covers the key stages of escalation between 1964 and 1968: the Gulf of Tonkin Resolution and its consequences, the bombing campaign known as Operation Rolling Thunder, the arrival of US Marines at Da Nang in March 1965, the search-and-destroy strategy pursued by General William Westmoreland, and the tactics and technologies used by both sides. It ends with the Tet Offensive, which, despite being a military defeat for North Vietnamese and Viet Cong forces, became the political turning point of the conflict — the moment after which Johnson declined to seek re-election and the United States began to look for a way out of the war.

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The Gulf of Tonkin Resolution and Johnson's Authority

The Gulf of Tonkin Resolution, passed by Congress on 7 August 1964, authorised the President "to take all necessary measures to repel any armed attack against the forces of the United States and to prevent further aggression". The resolution passed the House of Representatives 414–0 and the Senate 88–2. Only Senators Ernest Gruening of Alaska and Wayne Morse of Oregon dissented. Johnson treated the resolution as the functional equivalent of a declaration of war, although Congress had not formally declared one.

Johnson did not use the authority immediately. Running for the presidency against the Republican Senator Barry Goldwater, whose hawkish statements made him politically vulnerable, Johnson campaigned on a platform of restraint. His most famous campaign statement — "We are not about to send American boys nine or ten thousand miles away from home to do what Asian boys ought to be doing for themselves" — was delivered at Akron, Ohio on 21 October 1964. He won the election on 3 November 1964 by a margin of more than fifteen million votes, carrying 44 states. Within months of the inauguration he would use the Gulf of Tonkin Resolution as the basis for the sustained escalation that he had campaigned against.

Date	Event
2 August 1964	USS Maddox exchanges fire with North Vietnamese torpedo boats in the Gulf of Tonkin
4 August 1964	USS Maddox and USS Turner Joy report a second attack (later shown almost certainly not to have occurred)
7 August 1964	Congress passes the Gulf of Tonkin Resolution
3 November 1964	Johnson wins the presidential election against Barry Goldwater
7 February 1965	Viet Cong attack on US base at Pleiku kills 8 Americans
13 February 1965	Johnson authorises Operation Rolling Thunder

The attack on the US advisory compound at Pleiku on 7 February 1965, which killed eight Americans and wounded more than one hundred, provided the immediate trigger for the bombing campaign that followed. National Security Advisor McGeorge Bundy, on a fact-finding visit, witnessed the aftermath and cabled Johnson that the time for escalation had arrived.

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Operation Rolling Thunder and the Bombing Campaign

Operation Rolling Thunder, the sustained bombing of North Vietnam, began on 2 March 1965 and continued almost without pause for the next three and a half years, ending on 1 November 1968. Its stated objectives were threefold: to break the will of the government in Hanoi, to interdict the supply of men and material from North to South, and to raise the morale of the Saigon government. By the end of the campaign, American aircraft had dropped approximately 864,000 tons of ordnance on North Vietnam — more tonnage than had fallen on the entire Pacific theatre during the Second World War.

The bombing was calibrated carefully at the political level. Johnson personally reviewed target lists from the White House, and, fearing Chinese or Soviet intervention, refused to authorise strikes close to Hanoi, on the port of Haiphong (where Soviet shipping docked), or near the Chinese border. This gradualism, intended to signal American resolve while keeping the war limited, was later criticised by military commanders as allowing North Vietnam to adapt and by war opponents as producing the worst of both worlds — escalation without decisive effect.

The North Vietnamese adapted. Industry was dispersed, moved underground, or relocated to the Chinese border. Supplies from the Soviet Union and China arrived by rail and sea faster than bombing could destroy them. An elaborate air defence network of surface-to-air missiles (SAMs), anti-aircraft guns and MiG fighters — much of it Soviet-supplied and in some cases Soviet-operated — inflicted significant losses on US aircraft. Over the course of the campaign the United States lost more than 900 aircraft and several hundred aircrew; prisoners of war at "the Hanoi Hilton" included the future Senator John McCain, shot down over Hanoi in October 1967.

Alongside Rolling Thunder, the United States conducted a far larger tactical bombing campaign inside South Vietnam and, from 1969, a secret bombing campaign against Cambodia. By 1973 the total tonnage dropped by American aircraft on Indochina would exceed seven million tons — more than three times the total tonnage dropped by all sides in the Second World War.

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Ground Escalation: Da Nang to Half a Million Troops

On 8 March 1965, 3,500 United States Marines came ashore at Da Nang on the central coast of South Vietnam. Their stated mission was to secure the air base from which Rolling Thunder sorties were flown. Although described as a defensive deployment, Da Nang marked the moment at which the United States formally crossed from an advisory mission into a combat role. Within weeks the Marines were engaged in offensive patrols around the base.

Troop numbers rose very quickly. General William Westmoreland, the commander of Military Assistance Command Vietnam (MACV) from 1964, made repeated requests for reinforcement; Johnson approved them in the belief that a larger commitment could produce a decisive result without triggering a wider war.

Date	US troops in Vietnam
End of 1963	c. 16,300
End of 1964	c. 23,000
End of 1965	c. 184,000
End of 1966	c. 385,000
End of 1967	c. 485,000
Peak, April 1969	c. 543,000

The increase was not simply a matter of numbers. Helicopters, which had first arrived in quantity during Kennedy's advisory expansion, became the signature vehicle of the American war: the Bell UH-1 "Huey" was used for troop transport, medical evacuation, reconnaissance and close air support. The United States also deployed B-52 bombers (from Guam and Thailand), heavy artillery, M113 armoured personnel carriers, and chemical agents. By 1967 American forces in South Vietnam operated the largest military airlift in history.

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Search-and-Destroy and the Body Count

Westmoreland's operational doctrine was known as search-and-destroy. American units, typically company- or battalion-sized, were inserted by helicopter into suspected Viet Cong-controlled areas. Their task was to locate enemy forces, engage them with superior firepower, inflict heavy casualties, and then withdraw — rather than, as in a conventional war, occupy and hold territory. The measure of success was not ground taken but enemy killed: the body count.