Vietnam War: Gulf of Tonkin Incident

How It Helped Lead to Greater American Involvement in Vietnam

Photograph of President Lyndon B. Johnson's Midnight Address on Second Gulf of Tonkin Incident
Photograph of President Lyndon B. Johnson's Midnight Address on Second Gulf of Tonkin Incident. Photograph Courtesy of the National Archives & Records Administration

The Gulf of Tonkin Incident took place on Aug. 2 and 4, 1964, and helped lead to greater American involvement in the Vietnam War.

Fleets & Commanders

US Navy

  • Captain John J. Herrick
  • 1, then 2 destroyers

North Vietnam

  • 3 patrol boats

Gulf of Tonkin Incident Overview

Shortly after taking office following the death of President John F. Kennedy, President Lyndon B. Johnson became concerned about South Vietnam's ability to fend off the Communist Viet Cong guerillas that were operating in the country. Seeking to follow the established policy of containment, Johnson and his Secretary of Defense, Robert McNamara, began increasing military aid to South Vietnam. In an effort to increase pressure on North Vietnam, several Norwegian-built fast patrol boats (PTFs) were covertly purchased and transferred to South Vietnam.

These PTFs were manned by South Vietnamese crews and conducted a series of coastal attacks against targets in North Vietnam as part of Operation 34A. Originally begun by the Central Intelligence Agency in 1961, 34A was a highly-classified program of covert operations against North Vietnam. After several early failures, it was transferred to the Military Assistance Command, Vietnam Studies and Observations Group in 1964, at which time its focus shifted to maritime operations. In addition, the US Navy was instructed to conduct Desoto patrols off North Vietnam.

A long-standing program, the Desoto patrols consisted of American warships cruising in international waters to conduct electronic surveillance operations. These types of patrols had previously been conducted off the coasts of the Soviet Union, China, and North Korea. While 34A and the Desoto patrols were independent operations, the latter benefited from the increased signals traffic generated by the attacks of the former. As a result, the ships offshore were able to collect valuable information on North Vietnamese military capabilities.

The First Attack

On July 31, 1964, the destroyer USS Maddox commenced a Desoto patrol off North Vietnam. Under the operational control of Captain John J. Herrick, it steamed through the Gulf of Tonkin collecting intelligence. This mission coincided with several 34A attacks, including an Aug. 1 raid on Hon Me and Hon Ngu Islands. Unable to catch the fast South Vietnamese PTFs, the government in Hanoi elected to strike instead at USS Maddox. On the afternoon of Aug. 2, three Soviet-built P-4 motor torpedo boats were dispatched to attack the destroyer.

Cruising twenty-eight miles offshore in international waters, Maddox was approached by the North Vietnamese. Alerted to the threat, Herrick requested air support from the carrier USS Ticonderoga. This was granted, and four F-8 Crusaders were vectored towards Maddox's position. In addition, the destroyer USS Turner Joy began moving to support Maddox. Not reported at the time, Herrick instructed his gun crews to fire three warning shots if the North Vietnamese came within 10,000 yards of the ship. These warning shots were fired and the P-4s launched a torpedo attack.

Returning fire, Maddox scored hits on the P-4s while being struck by a single 14.5-millimeter machine gun bullet. After 15 minutes of maneuvering, the F-8s arrived and strafed the North Vietnamese boats, damaging two and leaving the third dead in the water. The threat removed, Maddox retired from the area to rejoin friendly forces. Surprised by the North Vietnamese response, Johnson decided that the United States could not back away from the challenge and directed his commanders in the Pacific to continue with the Desoto missions.

The Second Attack

Reinforced by Turner Joy, Herrick returned to the area on Aug. 4. That night and morning, while cruising in heavy weather, the ships received radar, radio, and sonar reports that signaled another North Vietnamese attack. Taking evasive action, they fired on numerous radar targets. After the incident, Herrick was unsure that his ships had been attacked, reporting at 1:27 a.m. Washington time that "Freak weather effects on radar and overeager sonarmen may have accounted for many reports. No actual visual sightings by Maddox."

After suggesting a "complete evaluation" of the affair before taking further action, he radioed requesting a "thorough reconnaissance in daylight by aircraft." American aircraft flying over the scene during the "attack" failed to spot any North Vietnamese boats.


While there was some doubt in Washington regarding the second attack, those aboard Maddox and Turner Joy were convinced that it had occurred. This along with flawed signals intelligence from the National Security Agency led Johnson to order retaliatory airstrikes against North Vietnam. Launching on Aug. 5, Operation Pierce Arrow saw aircraft from USS Ticonderoga and USS Constellation strike oil facilities at Vinh and attack approximately 30 North Vietnamese vessels. Subsequent research and declassified documents have essentially shown that the second attack did not happen. This was reinforced by statements by retired Vietnamese Defense Minister Vo Nguyen Giap who admitted to the Aug. 2 attack but denied ordering another two days later.

Shortly after ordering the airstrikes, Johnson went on television and addressed the nation regarding the incident. He then requested the passage of a resolution "expressing the unity and determination of the United States in supporting freedom and in protecting peace in Southeast Asia." Arguing that he did not seek a "wider war," Johnson stated the importance of showing that the United States would "continue to protect its national interests." Approved on Aug. 10, 1964, the Southeast Asia (Gulf of Tonkin) Resolution, gave Johnson the power to use military force in the region without requiring a declaration of war. Over the next few years, Johnson used the resolution to rapidly escalate American involvement in the Vietnam War.


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Your Citation
Hickman, Kennedy. "Vietnam War: Gulf of Tonkin Incident." ThoughtCo, Apr. 5, 2023, Hickman, Kennedy. (2023, April 5). Vietnam War: Gulf of Tonkin Incident. Retrieved from Hickman, Kennedy. "Vietnam War: Gulf of Tonkin Incident." ThoughtCo. (accessed June 9, 2023).