The McNamara Line and The Jason’s


    The McNamara Line was a project spearheaded by the clandestine JASON advisory group that was designed to get an advantage over the North Vietnamese freedom of movement on the Ho Chi Minh Trail.

    As destructive as war is, it creates things – often in ways peace-time cannot. Battlefield dilemmas spark innovation as governments, defense contractors, scientists, and the top brass convene in windowless rooms, developing the next advancement in technology or tactics that adapt to those of thy enemy. The United States (US) Secretary of Defense during part of the Vietnam War, Robert McNamara, knew this very well. And when it came to finding a solution to the problematic Ho Chi Minh Trail, a line had to be drawn – The McNamara Line.

    The Ho Chi Minh Trail

    For the United States, the Vietnam War was a prime setting for the testing and implementation of newly developed tech. The state of warfare had changed quite a bit since World War II, and the long duration of the Cold War and its proxies gave plenty of incentive for global superpowers to embark on the race for battlefield advancements. In the context of Vietnam, the Ho Chi Minh Trail was a piece of key terrain – whoever controlled it could have the upper hand in the seemingly never-ending conflict.  

    The trail, named after North Vietnamese leader Ho Chi Minh, was a network of trails spanning hundreds of miles and going from North Vietnam to South Vietnam, and crossing through the border countries of Laos and Cambodia along the way. This trail was significant to the North Vietnamese who used its labyrinthian paths as an administrative and logistical support route for shuttling troops and other resources to the South – the tactical issue the McNamara Line was created to address.

    McNamara Line

    According to a now declassified CIA memo about “Alternative Programs for Bombing North Vietnam”, analysts estimated “based on performance to date, that the actual movement of supplies from North Vietnam into Laos and South Vietnam during the 1966-1967 dry season will be greater than it was during the 1965-1966 dry season.” That same memo also stated “it is almost certain that no interdiction program can neutralize the logistics target system to the extent necessary to reduce the flow of men and supplies to South Vietnam below their present levels. Both of these quotes are in reference to the US bombing campaign on North Vietnam that was unsuccessful in cutting their administrative and logistical lines.

    Secretary McNamara along with his military advisors determined the trail to be a critical node to the success of the North Vietnamese. In his eyes, finding a way to impede the enemy’s capabilities along it would be detrimental for an eventual end to the war. In order to come up with a solution, McNamara mustered up the collective brainpower of the scientific supergroup known as “the Jasons” – a more intellectually driven alternative to the failed bombing campaign.

    McNamara Line


    “We’re doing this… for science…”        

    The JASON group, also known as the Jasons, were a collective of minds that came from the top shelf of the scientific community. The extent of their works was remained heavily classified, and to this day relatively unearthed to the general public. Nonetheless, they were a central role in helping McNamara cultivate his Ho Chi Minh Trail strategy.

    According to Science Magazine, “During the Vietnam War, the JASON group designed a forerunner to the electronic battlefield: an anti-infiltration barrier that linked hidden acoustic and seismic sensors on the ground to bombers and artillery.” This design was the byproduct of one of the Jasons annual summer studies taking place in 1966 on the campus of a preparatory school in the suburbs of Boston, Massachusetts – and then later moved to the University of California in Santa Barbara when the time came to tackle the Ho Chi Minh Trail problem. The anti-infiltration barrier/air-ground link solution the Jasons drafted can in essence be broken down into three stages:

    1. Large batches of acoustic and seismic sensors are placed around the jungle area along the trail. Each sensor had a specific sound to listen for (enemy voices, vehicles, troop movements that generate seismic waves, etc). Sensors were also emplaced that could detect distinct and relevant smells, such as ammonia which could signify an enemy presence.
    2. Signals from the ground sensors transmit to aircraft within the area of operations. Those aircraft transmit the signal back to mission specific centrally located computers with the capability of deciphering the signals and comparing and contrasting them with pre-programed examples. This was a way to mitigate false signals and differentiate between enemy and villagers (foreshadowing a bit).
    3. The computer would then conduct a calculation of target priorities and the transmit them to aircraft assets in the area of operations that would then carry out the strikes.

    This system was the primary component of the solution the Jasons had planned, which also included other methods of interrupting the North Vietnamese activity on the trail.

    Once the Jasons study was completed, a detachment of them met with Secretary McNamara to present the plan. In his book Kill Chain, author Andrew Cockburn writes “the secretary, who was very fond of neat technical solutions to human problems, was highly enthusiastic and ordered the air force to get to work immediately”. And with his blessing, the bottomless US defense budget accompanied the Jasons as they began the operation to construct the Ho Chi Minh Line – also known, as the McNamara Line – which included the worlds first implementation of an unmanned air-to-surface strike operation; the early precursor to the US’s contemporary drone program. McNamara’s intent was for the line to be defensive in nature – the US would chip away at the enemy’s logistics, impede reinforcements the freedom of movement into the South, and eventually pressure North Vietnam into surrender.

    The McNamara Line & Modern Drones: Parallels of Tragedy    

    The McNamara Line is an example of typical US fashion in modern wars. A serious threat is identified that requires an innovative plan, a bunch of money is tossed around, and stuff happens. As always, the primary intention is to end the war (for some that is…) and “bring the boys home”, and that usually means “by any means necessary”, even if some rather unpleasant collateral damage occurs along the way. I mean, what do a few civilian casualties’ matter? It is just war, right?

    And so it is, just war. And yes, there are indeed casualties in conflicts that have no part to play in the fighting, or even in support of either side. In the case of the McNamara Line, the line between conflict and government overstepping was heavily blurred.

    To revisit Kill Chain, Cockburn writes “For nine years, high explosives of all shapes and sizes had rained down out of the sky, killing men, women, and children and obliterating their homes and much of the old forest”. When these villagers in remote parts of Southeast Laos were questioned years later about the bombings, they would report confusion as to who the “enemy” was, despite it being who they claimed bombed them. Little did they know, that “A massive computer hundreds of miles away” was the source of their pain and hardship.

    This system, that was designed to put an end to the now second longest war in US history (thanks Afghanistan), was intended for good, but that good came at the price of innocent lives within geographical regions that were not even part of the conventional fighting in the Vietnam conflict. 

    The McNamara Line may be a thing of the past, but the advancements in automated battlefields that it sparked led the US to the development and eventual primary use of unmanned aerial systems in combat theaters. Much like the events leading up to the McNamara Line operation, the drone program is relatively secret, and lies in a sometimes-moral grey area with limited accountability or exterior oversight. According to the Bureau of Investigative Journalism, 910-2,200 civilians have been killed in drone strikes between 2004 and now. Additionally, 283-454 children have been killed in that same timeframe. In the most simplistic and general way of describing it possible, all those accidental deaths were carried out by the twitch of a finger muscle of someone in an air-conditioned windowless room in the United States.

    McNamara Line

    The parallels between the McNamara Line and the modern drone program are valuable to examine as a case study in both military innovation and strategy, as well as the sometimes-dark symptoms of the US governments “by any means necessary” approach to conflict, and the ethical concerns that come with an increasingly automated battlespace.

    There is of course a great need for a strong drone program, not just out of a position of matching the military capabilities of other global superpowers, but also as a way of conducting precision strikes on high value targets without risking the lives of boots on the ground. Weighing the pros and cons does nothing more but solidify how much tension there is between each side of the issue at hand.

    Michael Ellmer
    Michael Ellmer
    Michael is the Head of Research and Editor at Grey Dynamics. He spent eight years the United States Marine Corps infantry, and is currently pursuing a master’s degree in strategic intelligence analysis at Brunel University London.

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