Gulf of Tonkin incident
The Gulf of Tonkin incident set in motion one of the longest and most costly wars in American history, yet one of its two defining events never actually happened. On the night of the 4th of August 1964, two U.S. Navy destroyers opened fire on radar targets in the Gulf of Tonkin, reporting that North Vietnamese torpedo boats were attacking them. There were no torpedo boats. There was no attack. The ships were firing at shadows.
What followed was a cascade of decisions made in Washington on the basis of intelligence that the National Security Agency later admitted had been deliberately skewed. Congress passed a resolution granting President Lyndon B. Johnson sweeping authority to wage war across Southeast Asia. By early 1965, American forces were fighting openly in Vietnam.
How does a non-event become a war? The answer involves covert commando raids, a destroyer collecting signals intelligence along a hostile coast, a captain who immediately doubted his own crew's reports, and a White House that did not want to hear doubt. The questions worth carrying through this story are simple ones: what actually happened in the Gulf of Tonkin in August 1964, who knew what and when, and what was done with that knowledge.
Long before the events of August 1964, the United States was already running a secret war against North Vietnam. A classified program of covert operations called Operation Plan 34-Alpha had begun under the CIA in 1961. By 1964, the program had been transferred to the Defense Department and was being run by the Military Assistance Command, Vietnam Studies and Observations Group, known as MACV-SOG.
For the maritime portion of these operations, a set of fast patrol boats had been purchased quietly from Norway and delivered to South Vietnam. Three Norwegian skippers traveled to South Vietnam in 1963 on a covert mission; they had been recruited by Norwegian intelligence officer Alf Martens Meyer, who was operating on behalf of U.S. intelligence. The skippers did not know Meyer's true role when they signed on for what turned out to be sabotage missions against North Vietnam.
Although South Vietnamese naval personnel crewed the boats, approval for each mission came directly from Admiral U.S. Grant Sharp Jr., the Commander in Chief Pacific, based in Honolulu, who received his orders from the White House. When Hanoi lodged a complaint with the International Control Commission about the coastal attacks, the United States denied any involvement. Secretary McNamara admitted to Congress four years later that U.S. ships had in fact been cooperating in those South Vietnamese attacks.
Running alongside Operation Plan 34-Alpha was a separate intelligence-gathering program called DESOTO. Starting in 1962, the U.S. Navy used destroyer patrols in the western Pacific for electronic warfare support, collecting signals intelligence. The first DESOTO missions in the Gulf of Tonkin began in February 1964. While DESOTO intelligence could inform OPLAN-34A planners, the two programs were officially kept separate, with DESOTO patrols warned only to stay clear of 34A operational areas.
On the night of the 29th of July 1964, the night before the South Vietnamese launched attacks against North Vietnamese facilities on Hòn Mê and Hòn Ngư islands, MACV-SOG had also inserted a covert long-term agent team into North Vietnam. That team was promptly captured. On the 1st and the 2nd of August, CIA-sponsored Laotian fighter-bombers piloted by Thai mercenaries attacked border outposts well inside southwestern North Vietnam. According to historian Edwin Moïse, the Hanoi government almost certainly viewed all of these as coordinated moves to escalate military pressure.
The destroyer Maddox had begun her DESOTO mission in the Gulf of Tonkin on the 31st of July 1964. Her orders kept her at least eight miles from North Vietnam's coast and four miles from Hon Nieu island. When a MACV-SOG commando raid was carried out against Hon Nieu, Maddox was 120 miles away from the attacked area.
By the 1st of August, North Vietnamese patrol boats were tracking Maddox. Intercepted communications indicated they were preparing to attack. Maddox retreated, but resumed her routine patrol the following day. Three North Vietnamese P-4 torpedo boats then began to follow her. The boats were from Squadron 135, commanded by Le Duy Khoai. The three individual boats were commanded by brothers Van Bot, Van Tu, and Van Gian. With a top speed of 50 knots against the Maddox's 28 knots, the torpedo boats closed quickly.
As the P-4s approached from the southwest, Maddox changed course and increased speed to 25 knots. The ship fired three warning shots. The North Vietnamese boats attacked anyway, launching torpedoes and opening up with machine gun fire. Maddox's five-inch guns forced the torpedo boats back. Two of them had come as close as five nautical miles and each released one torpedo, but neither hit; Maddox evaded them and the torpedoes passed no closer than about 100 yards. A third P-4 received a direct hit from a five-inch shell, its torpedo malfunctioning at launch. Four U.S. Navy F-8 Crusader jets launched from the carrier USS Ticonderoga joined the fight 15 minutes after Maddox's first warning shots, attacking the withdrawing P-4s.
Maddox herself suffered only minor damage: a single 14.5 mm bullet from a P-4's KPV heavy machine gun struck her superstructure. Four North Vietnamese sailors were killed and six wounded. There were no U.S. casualties.
A 2001 internal NSA historical study later clarified a detail the Johnson administration had suppressed. At approximately 15:05 Gulf time, Maddox fired her initial three warning shots; that action was never disclosed by the administration, which maintained publicly that the North Vietnamese boats had fired first.
On the 3rd of August, the destroyer Turner Joy joined Maddox, and the two ships continued the DESOTO mission. That same day, President Johnson ordered both destroyers to conduct daylight runs into North Vietnamese waters to test what North Vietnam would do. Those runs coincided with South Vietnamese coastal raids and were interpreted by Hanoi as part of a coordinated operation.
On the evening of the 4th of August, during a night of rough weather and heavy seas, Maddox and Turner Joy reported receiving radar, sonar, and radio signals suggesting an imminent North Vietnamese attack. For roughly two hours, from about 21:40 to about 23:35 local time, the ships fired on radar targets and maneuvered sharply. Despite claims that two torpedo boats had been sunk, no wreckage, no bodies, and no other physical evidence appeared at the scene.
Captain John Herrick, commodore of the Maddox task force, quickly began to doubt what his crew had reported. At 01:27 local time, he sent a cable to his superiors: "Review of action makes many reported contacts and torpedoes fired appear doubtful. Freak weather effects on radar and overeager sonarmen may have accounted for many reports. No actual visual sightings by Maddox. Suggest complete evaluation before any further action taken."
Herrick sent a second cable one hour later. He wrote, "Entire action leaves many doubts except for apparent ambush at beginning." He again recommended a thorough reconnaissance by aircraft before any action was taken. By 18:00 Washington time, Herrick had cabled again with a further assessment: "the first boat to close the Maddox probably launched a torpedo at the Maddox which was heard but not seen. All subsequent Maddox torpedo reports are doubtful in that it is suspected that sonarman was hearing the ship's own propeller beat."
Squadron Commander James Stockdale was flying overhead during the second alleged attack. In his 1984 book Love and War, Stockdale wrote: "I had the best seat in the house to watch that event, and our destroyers were just shooting at phantom targets -- there were no PT boats there... There was nothing there but black water and American fire power." Stockdale said his superiors ordered him to keep quiet. After he was later captured, the knowledge became a heavy burden; he feared his captors would eventually force him to reveal what he knew.
While Herrick's cables expressing doubt were accumulating, the Johnson administration was moving rapidly toward a military response. Shortlyefore midnight on the 4th of August, Johnson interrupted national television to describe an attack by North Vietnamese vessels on Maddox and Turner Joy and to request authority for a military response. He described the incidents as having occurred "on the high seas," suggesting international waters.
Johnson also used the "hot line" to Moscow that same day, assuring the Soviets he had no intention of opening a broader war. Early on the 5th of August, he publicly ordered retaliatory measures. One hour and forty minutes after his speech, aircraft launched from U.S. carriers reached North Vietnamese targets. At 10:40 on the 5th of August, those planes bombed four torpedo boat bases and an oil storage facility in Vinh.
The administration's public version diverged sharply from what officials knew privately. In the face of growing uncertainties during the day of the 4th, the Johnson administration based its conclusion mostly on communications intercepts that were later shown to have been erroneously assessed. Those intercepts concerned the recovery of torpedo boats damaged in the 2nd of August attack and North Vietnamese observations of, but not participation in, the 4th of August U.S. actions.
McNamara later testified that he had read Herrick's doubtful cable after returning to the Pentagon that afternoon but did not immediately call Johnson to flag that the premise for retaliatory air strikes was highly questionable. Johnson himself commented privately: "For all I know, our navy was shooting at whales out there."
Publications including Time, Life, and Newsweek ran articles throughout August presenting the Tonkin Gulf incident as a clear-cut North Vietnamese attack. Time reported that the attackers had opened fire from as close as 2,000 yards, and stated that there was "no doubt in Sharp's mind" and no debate within the administration. Neither claim held up.
On the 7th of August 1964, Congress passed a joint resolution, H.J. RES 1145, titled the Southeast Asia Resolution. It granted Johnson authority to "take all necessary steps, including the use of armed force, to assist any member or protocol state of the Southeast Asia Collective Defense Treaty requesting assistance in defense of its freedom." The resolution became Johnson's legal basis for deploying conventional U.S. forces to South Vietnam and for commencing open warfare against North Vietnam in early 1965.
Senator Wayne Morse had tried to slow the resolution. He had reportedly received a call from an anonymous informant urging him to investigate the official logbooks of Maddox, which were not made available to Congress before the vote. Morse argued on the floor that the United States had taken "acts of war rather than acts of defense" outside the bounds of the Constitution. His efforts failed to gain traction, largely because he could not reveal his source and was working with limited information. It was only after the United States became more deeply involved in the war that his position began to gain wider support in the government.
In 1967, former naval officer John White wrote a letter to the editor of the New Haven Register asserting that Johnson, McNamara, and the Joint Chiefs of Staff had given false information to Congress about the Gulf of Tonkin attacks. White continued his efforts in the 1968 documentary In the Year of the Pig. In 2014, as the incident's 50th anniversary approached, White published a book on the subject. In its foreword, he noted that a handful of the many books written on the Vietnam War had cited his 1967 letter as having pressured the Johnson administration toward truth about how the war started.
The Gulf of Tonkin incident also rippled outward to China, where it heightened fears among Chinese Communist Party leadership that the United States would eventually invade China. That fear increased support among leadership for Mao Zedong's Third Front Construction campaign, which aimed to develop heavy industry and defense industries in China's interior where they would be better protected in the event of a foreign invasion.
Doubt about the 4th of August incident surfaced almost immediately in 1964, but the conclusive proof took decades to emerge. In 1981, Captain Herrick and journalist Robert Scheer re-examined Herrick's ship's log and determined that even the initial torpedo report from that night, which Herrick had long maintained was an "apparent ambush," was in fact unfounded.
In 1995, McNamara met with former North Vietnamese Army General Võ Nguyên Giáp to ask directly what had happened on the 4th of August 1964. "Absolutely nothing," Giáp replied. Giáp confirmed that the attack had been imaginary, while acknowledging that North Vietnamese vessels did attack on the 2nd of August.
In 2003, McNamara appeared in the documentary The Fog of War and admitted on camera that there had been no attack on the 4th of August. A taped conversation from several weeks after the passage of the Gulf of Tonkin Resolution was also released in 2001, revealing that McNamara had expressed doubts to Johnson about whether the attack had ever occurred.
The sharpest institutional accounting came from inside the NSA itself. In October 2005, reporting in The New York Times revealed that NSA historian Robert J. Hanyok had concluded that NSA staff had deliberately skewed intelligence reports to make it appear that an attack had occurred. Hanyok's conclusions had first been published in the Winter 2000/Spring 2001 edition of Cryptologic Quarterly, roughly five years before the Times article. Officials said the view that Hanyok's report should be made public was rebuffed by policy makers concerned that comparisons would be drawn to intelligence used to justify the Iraq War, which had begun in 2003.
Hanyok found that the sequence began at Phu Bai, where analysts mistakenly believed an attack was imminent. As the evening progressed, the 90% of signals intelligence that did not support the conclusion of an attack was excluded from NSA reports sent to the president. Hanyok attributed this partly to the deference the NSA gave to analysts who were physically closer to the event. He also pointed to the atmosphere in Washington: Ray Cline was quoted in Hanyok's study as saying, "We knew it was bum dope that we were getting from Seventh Fleet, but we were told only to give facts with no elaboration on the nature of the evidence. Everyone knew how volatile LBJ was. He did not like to deal with uncertainties."
On the 30th of November 2005, the NSA released a first installment of previously classified documents on the Gulf of Tonkin incident, including a sanitized version of Hanyok's article. A fuller history of NSA involvement in the Indochina Wars, including Hanyok's chapter on Tonkin Gulf, was released by the NSA in January 2008 and published by the Federation of American Scientists.
Updated
Common questions
Did the Gulf of Tonkin attack on 4 August 1964 actually happen?
No. The 4th of August 1964 attack was never real. Declassified NSA documents, the 2005 Hanyok study, and admissions by former Secretary of Defense Robert McNamara and former North Vietnamese General Võ Nguyên Giáp all confirmed that no North Vietnamese vessels were present that night. The 2nd of August engagement was real; the 4th of August one was not.
What was the Gulf of Tonkin Resolution and what did it authorize?
Congress passed the Gulf of Tonkin Resolution, formally H.J. RES 1145 and titled the Southeast Asia Resolution, on the 7th of August 1964. It authorized President Lyndon B. Johnson to take all necessary steps, including the use of armed force, to assist any Southeast Asian state whose government was threatened by communist aggression. Johnson used it as the legal basis for deploying conventional U.S. forces to South Vietnam and for commencing open warfare against North Vietnam in early 1965.
What did NSA historian Robert Hanyok find about the Gulf of Tonkin intelligence?
Hanyok concluded that NSA staff deliberately skewed intelligence reports to create the impression that an attack on U.S. destroyers had occurred on the 4th of August 1964. His findings were first published in the Winter 2000/Spring 2001 edition of Cryptologic Quarterly. The NSA released a sanitized version of his study on the 30th of November 2005, and a broader NSA history including his chapter was released in January 2008.
What was Operation Plan 34-Alpha and how did it relate to the Gulf of Tonkin incident?
Operation Plan 34-Alpha was a highly classified U.S. covert action program against North Vietnam that began under the CIA in 1961 and was transferred to the Defense Department in 1964. It ran South Vietnamese commando raids against North Vietnamese coastal targets, using fast patrol boats purchased quietly from Norway. These raids were ongoing in the days immediately before the Maddox encounter, and North Vietnam likely viewed them as part of a coordinated escalation that also included the Maddox's DESOTO intelligence patrol.
What did Captain John Herrick report about the 4 August 1964 Gulf of Tonkin attack?
Captain Herrick, commander of the Maddox task force, cabled his superiors at 01:27 local time on the 4th of August that many reported contacts and torpedoes appeared doubtful, citing freak weather effects on radar and overeager sonarmen. He sent multiple follow-up cables recommending a complete evaluation before any further action, and by 18:00 Washington time concluded that most torpedo reports were likely the sonarman hearing the ship's own propeller beat.
What did James Stockdale say about the second Gulf of Tonkin incident?
Squadron Commander James Stockdale was flying overhead during the 4th of August engagement. In his 1984 book Love and War, he wrote that he had the best seat in the house and that the destroyers were shooting at phantom targets with nothing there but black water and American firepower. His superiors ordered him to keep quiet, and after his later capture he feared his captors would force him to reveal what he knew.
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