At the earliest stages of major US involvement in Vietnam, military strategists recognized that North Vietnam’s ability to use the Ho Chi Minh Trail to re-supply their forces in the south had to be curtailed. In reviewing their options, their thoughts turned to air power as a means of disrupting the North Vietnamese communications network and forcing Hanoi to enter into serious negotiations for peace with minimal risk to American personnel. Another objective, advocated by officials such as McGeorge Bundy, Johnson’s national security advisor, was to “bolster South Vietnamese morale and reaffirm the credibility of the American commitment to resist revolutionary activity in the Third World.”

Although the aims of the bombing campaign were widely shared, there was much debate over the timing, method, and intensity of the bombing. Robert A. Pape, a military historian who has written extensively on the theory and practice of airpower, identified three competing strategies that were current in 1966: the Civilian strategy, the Air Force strategy, and the Army strategy.

As described by Pape, American proponents of the Civilian strategy believed that North Vietnam could be coerced by gradually increasing threats to its population and economy. This approach called for a limited bombing campaign, characterized by a gradual increase in force, mounting pressure on industry, carefully orchestrated acceleration of tempo, and the promise of inevitable and ultimate destruction.

Key advocates of the strategy-who included Defense Secretary Robert McNamara, Deputy National Security Advisor Walt W. Rostow, and Assistant Secretary of State William Bundy- believed that subjecting the North Vietnamese industrial economy to gradually increasing risk would create a powerful incentive for Hanoi to curtail its support for the insurgency to ensure the survival of its nascent industrial economy. For the civilian leadership, nuclear weapons were only useful to threaten the Vietnamese and their Chinese and Soviet allies, and to hedge against Chinese intervention.

In contrast to the civilian plan, the Air Force strategy was not just to threaten, but to destroy, the North’s industrial base. Proponents such as General Curtis E. Le May, then Air Force Chief of Staff, and his successor General John P. McConnell believed that the destruction of North Vietnam’s industrial war potential would wreak havoc on the country’s political and social fabric. Their goal was to obliterate all industrial and major transportation targets as quickly as possible, to sink the morale of the military and to sow fear among the people. For this strategy, the military wanted relief from politically-imposed “no bombing” zones, not extra firepower to attack such targets derived from nuclear weapons. There was low-level discussion of using nuclear weapons to attack the dykes north of Hanoi in late 1966, but this loose talk never made it into formal evaluation, according to one participant at the time.

The Army strategy focused on undermining Hanoi’s support for the southern insurgency by limiting the flow of men and equipment to the south. Joint Chiefs of Staff Chairman General Earle G. Wheeler, Army Chief of Staff General Harold K. Johnson, and other supporters of the plan wanted to thwart the North Vietnamese ability to succeed on the battlefields of the South by reducing the rate of delivery of support to the Viet Cong below their minimum sustaining level. This counter-insurgency strategy had the most to gain from employing tactical nuclear weapons. In many respects, the JASON study took the Army strategy as its point of reference.

The upshot of the debate was to convince the Johnson administration to initiate a major series of bombing campaigns against North Vietnam known as Rolling Thunder (2 March 1965-31 October 1968). The first phase of the air campaign, carried out in spring-summer 1965, followed the lenient, gradual civilian model and focused on a list of fixed military and transportation targets, one of the most important of which was a 33.3-square mile region known as the Mu Gia pass.