How Close Did the United States Actually Get to Using Nuclear Weapons in Vietnam in 1968?


In their critically acclaimed comic book series, Watchmen, Alan Moore and Dave Gibbons render an alternate, dystopian 1985 America in which the United States won the Vietnam War after obliterating North Vietnamese forces through the deployment of Dr. Manhattan, a one-time nuclear physicist transformed into a supernatural being by a radiation experiment gone awry. Within weeks of unleashing Dr. Manhattan’s destructive powers on the battlefield, North Vietnamese soldiers laid down their arms in defeat. “Often they surrender to me personally,” Dr. Manhattan recalls, “their terror of me balanced by an almost religious awe. I am reminded of how the Japanese were reported to have viewed the atomic bomb, after Hiroshima.”

In an eerie twist on life imitating art, recent news coverage suggests just such a reality could have come to pass. The publication of Michael Beschloss’ new book, Presidents of War, shined light on declassified documents describing the efforts that President Lyndon Johnson’s senior military officers undertook without presidential authorization in early 1968 to prepare for the use of tactical nuclear weapons in Vietnam.

How close did the United States actually get to deploying nuclear weapons in Vietnam in 1968? Who initiated this plan, codenamed “Fracture Jaw,” and when did the president become aware of it? What can today’s leaders learn from this incident, and what implications does this episode have for command and control of nuclear weapons during wartime and the so-called “nuclear taboo” that purportedly dissuades their use?

Drawing on declassified “eyes only” materials housed at the Lyndon Johnson Presidential Library in Austin, Texas, I seek to situate the revelations in Beschloss’ book in the broader historical context to provide a more detailed account of the military’s planning for Fracture Jaw and just how far Pentagon and White House officials allowed these preparations to progress without the president’s full knowledge.

The story these documents tell is not altogether new. By the mid-2000s, Nina Tannenwald and documents declassified by the State Department had already revealed that Johnson shut down the military’s 1968 contingency planning for the employment of tactical nuclear weapons in the Vietnam war. The most recently declassified documents, however, convey just how far this planning had advanced at Pacific Command before press disclosures in Washington brought the full scope and scale of Fracture Jaw to the attention of a furious president and a beleaguered White House.

In one sense, the story is reassuring. Johnson halted the deployment of these weapons at a moment in Vietnam when he would have faced considerable pressure from his theater commanders to use them. But it is also an alarming tale because tactical nuclear weapons planning got underway absent advance knowledge of — let alone authorization from — the commander-in-chief. As the 2018 Nuclear Posture Review calls for an expansion of America’s low-yield tactical nuclear options, policymakers and operational planners would benefit from understanding the importance of coordinating their contingency planning across civilian and military authorities to preserve the integrity of the command and control infrastructure and avoid the missteps of Fracture Jaw.

1968: “Thank God January is Ending”

The debate over Fracture Jaw took place in in the midst of a swirling sea of national security crises in early 1968. Intelligence reports indicated Hanoi was amassing a substantial number of forces northwest of the demilitarized zone in preparation for a major offensive against the allied base in Khe Sanh, an attack that Johnson worried would be his Dien Bien Phu. According to one CIA assessment, North Vietnamese forces sought not merely to lay siege to the base but also “draw U.S. reinforcements into the area, tie them down to static defense positions, and inflict maximum casualties on U.S. forces for a period of time.”

In addition to the anticipated assault on Khe Sanh, the Johnson administration also confronted the attempted assassination of the South Korean president on Jan. 21 and the seizure of the U.S.S. Pueblo on Jan. 23 by North Korean forces. During the same week, a B-52 bomber carrying four thermonuclear bombs crash-landed near Greenland’s Thule Air Force base. And on Jan. 29, Hanoi launched the first wave of the 1968 Tet Offensive, where approximately 84,000 North Vietnamese forces and Viet Cong guerillas launched a series of coordinated surprise attacks against more than 100 cities throughout South Vietnam, including the capital city of Saigon. In the final hours of Jan. 31, National Security Advisor Walt Rostow informed the president that a modified American attack bomber had inadvertently strayed into Chinese airspace off the coast of Hainan. He signed off his memorandum with a confession that no doubt captured the feelings of all those in the West Wing: “thank God January is ending.”

Operation Fracture Jaw: Tactical Nuclear Contingency Planning “Well Underway”

February would prove no more auspicious. It was in this wave of unfolding national security crises that the president’s senior military advisors began actively preparing for the possible use of tactical nuclear weapons in Vietnam with new urgency. This was hardly the first time that the issue had been raised in the Vietnam War: even before the first U.S. ground forces landed at Da Nang, the Joint Chiefs of Staff had contemplated using nuclear weapons, and throughout 1966 and 1967, Joint Chiefs of Staff Chairman Earle Wheeler and Gen. William Westmoreland, commander of U.S. forces in Vietnam, lobbied the White House for a more aggressive aerial bombing strategy that envisioned potentially using these weapons against North Vietnamese military positions, supply lines, and support infrastructure. These deliberations gave rise to a number of studies, including a March 1966 memorandum from the CIA and a 55-page Pentagon-funded report in March 1967, underscoring how the political consequences of employing these weapons on the battlefield would far outweigh their meager operational benefits.

These pessimistic assessments seem to have done little to discourage renewed consideration of tactical nuclear weapons use in Vietnam in early 1968. Robert Ginsburgh, a military aide on the National Security Council and liaison to the Joint Chiefs, raised the issue in a Jan. 31 memorandum to Gen. Wheeler. “If, despite General Westmoreland’s best estimate, the situation at Khe Sanh should become desperate, the issue of using TAC NUCS will be raised,” Ginsburgh wrote. He then suggested a back channel with Westmoreland be established, cautioning that the plans should be “very very very closely held.”

The following morning, Feb. 1, Wheeler wrote to Westmoreland and Adm. Ulysses S.G. Sharp, commander of Pacific Command, that the handwringing in Washington over Khe Sanh was prompting questions about whether tactical nuclear weapons would be needed should the situation become sufficiently desperate. “I consider such an eventuality unlikely,” Wheeler continued:

Nevertheless, I would appreciate your views as to whether there are targets in the area which lend themselves to nuclear strikes, whether some contingency nuclear planning would be in order, and what you would consider to be some of the more significant pros and cons of using tac nukes in such a contingency.

Sharp replied on Feb. 1 that he and Westmoreland had already discussed the issue and that such planning was “well underway” by a special planning group in Okinawa operating “under the strictest security” with the codename “Fracture Jaw.” Although he considered the possibility that tactical nuclear weapons would be used “very remote,” Sharp insisted that “military prudence alone” required some detailed planning on the warhead yields and the delivery systems that would be used in such an eventuality.

At the White House, this contingency planning seems to have been initiated without the president’s knowledge and even that of his top national security officials. The issue first appears to have been brought to the president’s attention in a Feb. 2 memorandum from National Security Adviser Walt Rostow, who refers only obliquely to “a desire to avoid a situation of battlefield crisis in which Westy and the JCS would ask you to release tactical nuclear weapons. I have felt that every action ought to be taken now that could prevent such a circumstance from arising.”

Rostow made no direct mention of the preparations that were underway at Pacific Command, either because he himself lacked this knowledge or did not want to disclose them to the president for fear of incurring his wrath. He nevertheless advised Johnson to communicate privately to Gen. Wheeler “that it is his duty to minimize the likelihood that the nuclear issue would be raised by the JCS.”

Johnson spoke with Wheeler later that evening on the 2nd. In response to Johnson’s phone call, Wheeler forwarded a message from Westmoreland where he reiterated his belief that the “use of tactical nuclear weapons should not be required in the present situation” given the other firepower at his disposal. “However,” Westmoreland cautioned, “should the situation in the DMZ area change dramatically, we should be prepared to introduce weapons of greater effectiveness against massed forces. Under such circumstances, I visualize that either tactical nuclear weapons or chemical agents would be active candidates for employment.”

No contemporaneous record exists of Johnson’s reaction to this news, but Rostow’s memorandum to the president the next day, Feb. 3, suggests he was not pleased. Seemingly in response to an inquiry about the provenance of this planning, Rostow wrote he had authorized Robert Ginsburgh to discuss the matter “informally” with Wheeler with the understanding that “this was in no sense a ‘White House request’” and that “the matter had never been raised with the president, let alone by the president.” Rostow acknowledged that he did not anticipate “any formal staff work” would be set in motion as a result of these discussions. “The fault, therefore, is mine,” he concluded.

Planning Persists: Leaks, Presidential Fury, and the Fallout from Fracture Jaw

Back at Pacific Command headquarters, Fracture Jaw preparations continued unabated. In a Feb. 7 memorandum, Adm. Sharp indicated that the contingency plan drawn up by the special planning group in Okinawa “appears conceptually sound and contains the details necessary for implementation.” He asked Westmoreland to send his own operational plan to Pacific Command headquarters “on an expedited basis” so they could be incorporated into the group’s broader blueprint for Fracture Jaw, which Westmoreland indicated he would do after approving them on Feb. 10.

Within hours, Wheeler cabled Sharp with a single-sentence directive:

I request that you not repeat not forward any plans which you develop under the Fracture Jaw project until the JCS ask for them, or until a critical situation arises which, in your judgment, dictates the need for us to consider such plans.

On Feb. 12, Sharp directed Westmoreland to “discontinue all planning for Fracture Jaw” and “debrief all personnel with access to this planning project that there can be no disclosure of the content of the plan or knowledge that such planning was either underway or suspended.” Protection of all planning material, Sharp instructed, “must be air tight.”

How can we account for this abrupt about-face in Pacific Command’s planning for Fracture Jaw? The trigger appears to have been the airing of a Feb. 9 interview with Sen. Eugene McCarthy, Johnson’s challenger for the Democratic presidential nomination, who said he was aware of demands being made for the use of tactical nuclear weapons in Vietnam. Speculation intensified when Sen. William Fulbright, chairman of the Senate Foreign Relations Committee, sent a letter the same day to Secretary of State Dean Rusk asking about reports of a team of nuclear specialists who had visited South Vietnam the previous week (incidentally, to investigate a different covert program).

These swirling rumors in the press appear to have left Johnson furious and blindsided by the continued operational planning of his own military. “When he learned that the planning had been set in motion, he was extraordinarily upset,” recalled Tom Johnson, one of the president’s aides, “and he forcefully sent word through Rostow, and I think directly to Westmoreland himself, to shut it down.”

The president’s fury also prompted Rostow to write another “eyes only” memorandum reiterating the White House’s limited role in the military’s nuclear contingency planning. In response to a series of questions Johnson posed to him on the morning of Feb. 10, Rostow had to reassure the president that no action had been taken to deploy these weapons in theater. “There are no nuclear weapons in South Vietnam,” Rostow wrote. “Presidential authority would be required to put them there.”

Johnson seemed to still be fuming about the issue in a meeting with his senior foreign policy advisors later that afternoon. As Rusk started discussing a possible visit to South Vietnam by his deputy, Johnson appears to have cut off him off and pivoted to a topic searing in his mind. “Is it true there are no nuclear weapons in Vietnam?” Johnson snapped at his defense secretary. “It is true there are none there,” McNamara responded. “Do you expect any more trouble on the nuclear matter?” Johnson asked. “No, I think it will die down,” George Clinton, his press secretary responded.

Speculation, however, did not die down until the president himself addressed the matter directly in a Feb. 16 press conference. After warning the press that public discussion of nuclear weapons deployments threatened national security, Johnson said that, as far as he was aware, the Joint Chiefs and his secretaries of state and defense “have at no time ever considered or made a recommendation in any respect to the employment of nuclear weapons.”

The president chose his words carefully. Neither the Joint Chiefs nor his civilian national security advisors had indeed considered or made a recommendation as to the employment of these weapons. The deployment of tactical nuclear weapons to Vietnam, on the other hand, appears to have been on their minds over the course of the ill-fated Fracture Jaw operation.

The “Nuclear Taboo” and Command and Control Nuclear Weapons During Wartime

From the perspective of the so-called “nuclear taboo,” which dissuades the use of nuclear weapons because of their devastating destructive potential, the Fracture Jaw episode is something of a success story. Johnson consistently made clear to his advisors that he did not want to be put in a position where he would be asked for authority to launch tactical nuclear weapons in Vietnam. Although he did not explicitly rule out the use of these weapons categorically, Johnson’s fury in discovering on Feb. 10 that planning had persisted in spite of his earlier directive only reinforces the notion that the president was committed to avoiding their use.

From the vantage point of command and control of the nuclear arsenal, however, this episode is more harrowing. Although the president’s regional and theater commanders expeditiously complied with the commander-in-chief’s directive to shut down Fracture Jaw, their planning had progressed with seemingly little presidential understanding of just how far along Pacific Command had advanced in preparing its tactical nuclear arsenal for possible use.

Contingency planning is not a problem in and of itself. Indeed, the credibility of nuclear deterrence threats rests in large part on having a viable plan to use these weapons. And as custodians of the nuclear stockpile, the military not surprisingly plays a lead role in such planning. But the latitude afforded military professionals to develop such plans and manage the arsenal autonomously from their civilian overseers has waxed and waned over time, with some presidents asserting greater control over the arsenal and others delegating more authority to their military subordinates. And important differences in the ways that military professionals and civilian policymakers think about these weapons can become the source of significant civil-military tensions during wartime.

The close-hold nature of Fracture Jaw suggests that Johnson’s top military advisors were at least sensitive to the political ramifications of undertaking contingency planning for the use of tactical nuclear weapons. From an operational perspective, however, nuclear weapons exist on a continuum of armaments in the minds of some commanders, distinguished only by their destructive payload relative to high-yield conventional weapons. Westmoreland appears to have been interested primarily in delivering enough firepower to achieve battlefield success, which he felt could be accomplished using largescale conventional munitions, not unlike “the Mother of All Bombs” dropped in Afghanistan in April 2017. If battlefield conditions worsened, however, Westmoreland made clear he would seek authorities to use the next graduated weapon in the arsenal.

In his role as commander-in-chief, the president retains ultimate (and effectively unchecked) authority over whether to deploy nuclear weapons, a choice Johnson described as “one of the most awesome and grave decisions any president could be called upon to make.” In this instance, Johnson did not hesitate to exercise this authority, but only after media speculation made him aware of how far preparations for their use in Vietnam had actually progressed. That the president and the White House staff was insufficiently aware of how far along this contingency planning had progressed rightfully raises important questions about the integrity of the country’s nuclear command and control infrastructure, particularly as the United States contemplates a greater reliance on tactical nuclear weapons in its deterrence posture. And it gives rise to speculation, however remote, about the decision Johnson would have had to confront in weighing a full-fledged nuclear option in Vietnam should Fracture Jaw have come to fruition.

Theo Milonopoulos is a Ph.D. candidate in political science at Columbia University. He gratefully acknowledges the financial support of the LBJ Foundation and Moody Foundation of Galveston, Texas, as well as the assistance of archivist John Wilson at the Lyndon Baines Johnson Library for making this research possible. He also thanks Erik Lin-Greenberg for helpful feedback on an earlier draft of this article.

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