Topography and Tactics

The American military activity in Vietnam was unlike any previous campaign to be waged before it and set the stage for contemporary military tactics. Military doctrine from World War II was more-or-less discarded by 1965 to be replaced by search and destroy missions, massive air bombing campaigns and air mobile cavalry. The decision to discard old tactics was primarily the result of considerations of the topography of the rugged country.

Vietnam is broken up into five primary regions: in the North it is comprised of the Northern Highlands and Red River Delta and in the south is made up of the Annamite Mountain Range, Coastal Lowlands and Mekong Delta. Before the war forests densely covered 75% of the country,[1] which by 1980 had been reduced to 23% coverage by virtue of unceasing bombing. Over 80% of the country is either hills or mountainous. The terrain made World War II concepts of defense in depth, armored pincer attacks, encirclement and fixed defense nearly impossible to execute, as free movement was hindered by impassable elevation, muddy fields, prohibitively dense jungle and rice patties. The area of Vietnam was littered with pockets of impassable terrain that made contiguous lines meaningless and restricted the sort of total destruction tactics of fast moving armor forces during World War II:

[2]

Complicating the terrain of Vietnam was also the manner in which Viet Cong forces utilized it. While the French-trained ARVN operated along roads and utilized American-granted armor as mobile pillboxes, based around strong stations of defense, the VC struck from more difficult terrain and moved rapidly with light kit, ambushing and then retreating to terrain in which armor and heavy infantry could not easily pursue. When the VC forces were encountered by superior forces, they simply broke up and scattered, meeting at a safe area once the enemy had exfiltrated. Viet Cong and North Vietnamese battle tactics invariably followed a simple formula, adopted originally from the Chinese combat doctrine of Mao Tse-tung: When the enemy advances, withdraw; when he defends, harass; when he is tired, attack; when he withdraws, pursue. Communist forces operated in a decentralized fashion which emphasized extensive elasticity, planning, small unit actions and rapid assault and withdrawal. Small local VC units would congregate during carefully planned offensives into regimental and battalion-sized units and quickly attack, when met with enemy reinforcements would rapidly scatter and return to the jungle and mountains, the more deliberate, centralized and combined arms approach of the ARVN and US forces unable to compensate for a pursuit.

As Vietnam was not a region populated by large industrial centers as it was in Europe but rather by spread out modest sized villages and hamlets the ARVN and American response to these sort of raids demanded a different tactic, although ultimately the solutions proposed were neither effective or systematic. The allied forces had no fixed base to counter-attack, no staging ground or division headquarters; they would be attacked by enemy forces who would seemingly disappear into the thick jungle brush and roving mountains, left with casualties and destroyed vehicles but with no apparent object to retaliate against. Early in the conflict the “strategic hamlet” strategy employed by Diem sought to remedy this problem by relocating peasants from their ancestral homelands scattered across the countryside into densely populated and well fortified towns. This strategy failed due to the political instability of the Republic of Vietnam: the hamlets were inconsistently equipped, and where they were not, they fell into the hands of rival factions who were vying for power, most notably the VC, who exploited the discontent of villagers evicted from their land by infiltrating the supposedly secure hamlets and recruiting support. As coup after coup afflicted the Republic the strategic hamlets increasingly were neglected and eventually were absorbed by Communist forces.

The US forces approached the problem of having no fixed enemy positions to attack by seeking to deprive the whole region of supplies by virtue of massive bombing campaigns along the Ho Chi Minh Trail, an air war which would come to be known as Operation Rolling Thunder. Rolling Thunder also was designed to demoralize the enemy into capitulation. This latter point was emphasized by a series of deliberate lulls in the bombing campaign which were intended to offer a moment of pause in which the Hanoi government could submit their terms. The NVA and VC forces instead used these pauses to repair infrastructure damage and to expand Ho Chi Minh Trail logistics, restoring whatever damage the ultimately futile bombing regimen had inflicted. Under thick jungle cover and by tunneling into the mountains and hills of the region VC forces were capable of repairing damage and by use of simple hand tools, creating new supply lines. The tremendous scope of the operation, in which more bombs were dropped in a three year period than in the entirety of World War II,[3] intended to “shock and awe” the Hanoi government into at least accepting a status quo ante bellum, was absorbed and repelled by the determined Communist forces; Rolling Thunder failed to accomplish a single outlined objective.

While Rolling Thunder was intended to cut off the supply to Communist forces in the region a second aspect of the US’ new strategy was to locate and destroy the weakened pockets of insurgents in South Vietnam by means of sweeping foot patrols and ambush along suspected VC trails, supported by artillery from fortified firebases. This strategy was divided into two aspects: Search and Secure (S&S) and Search and Destroy (S&D). Search and Secure was intended to deploy a patrol into an area suspected of enemy activity, to locate an enemy stronghold, to attack, capture and secure it. Repeating the mistakes of the French, when this tactic was employed, the forward line of the American forces was extended and the adjacent rear neglected, often VC forces would re-infiltrate areas previously marked “secure.” The Communist forces, remaining faithful to an elastic strategy, would not commonly mass against the American fortified bases, but instead withdraw from the area completely after initial skirmishes and relocate to undefended regions. The US high command themselves attempted to adopt a similar strategy in Search and Destroy, in which foot patrols were dispatched into the countryside to rapidly ambush and withdraw from the Vietcong, the main objective being the destruction of enemy forces.

Search and Secure and Search and Destroy were integral parts of General Westmoreland’s three-phase strategy for repelling the Communist insurgency. By November 1963 over 40% of the countryside was in VC control.[4] Westmoreland designated the primary objective of the war as being a return of the region to the effective control of the Saigon government, made possible in three distinct steps[5]: (1) Slowing down and containing the VC offensive (Operation Rolling Thunder), (2) resuming the offensive and engaging VC forces (S&S and S&D), (3) returning South Vietnam government control. As we have seen, phase 1 of the operation was a failure; Operation Rolling Thunder had no significant effect on hindering the movement and reinforcement of Communist forces. Because VC and NVA forces were not hindered in reinforcing losses, materiel and supplies, the Search and Destroy missions did not inflict enough damage to defeat the enemy on a theatre-size level, and were incapable of stopping the gradual buildup of NVA troops which by the end of the war would enable the Communists to wage total war. As the VC forces were highly elastic and mobile, and as their logistical lines of supply and reinforcement were flexible and easily shifted, Search and Secure missions succeeded in only capturing meaningless ground; the enemy withdrew seamlessly and without loss to reestablish their presence elsewhere. By the end of the war the paltry affect Rolling Thunder had had in 1963-1965 was dwarfed by new complexes of VC tunnel systems which made aerial bombardment all but meaningless. Heavy jungle cover allowed VC to build the tunnels virtually undetected, and once they were in place, they served as nearly impenetrable lines of supply and reinforcement, the US Air Force serving no munition capable of soundly penetrating and destroying them.

In order to counter the impassable swathes of terrain scattered throughout the region and to adapt to the rapid movements of VC forces the US Army designed the world’s first Air Cavalry units. Equipped with combat helicopters, “air cav” was designated to deploy heavy infantry into the midst of enemy positions for quick assaults while supplies were continually ferried in and the wounded extracted by the rotary wing aircraft. While most instances of these sorts of assaults were successful in scattering massed NVA or Vietcong positions, as at the Battle of Ia Drang, consequent extraction resulted in a return to the status quo. While air cav was capable of overcoming difficult terrain it did not address the fundamental problem of subduing large swathes of countryside which was sympathetic to Communist sentiment. US tactics tended to emphasize massive attack, which it was quite successful in waging, but it lacked the capacity to permanently secure regions, a flaw which I think clearly echoes military strategy today. The systematic approach to warfare of World War II has been replaced, as it was in Vietnam, by dizzying displays of firepower in an attempt to demoralize and destroy the enemy without need of a crucial defense-in-depth or regular infantry advance. The Communists won the war because they did not so recklessly indulge in indiscriminate carnage and tended to emphasize meticulous planning. While the US forces tended to react to enemy activity (which they interpreted as being the work of unorganized guerillas and bandits[6]), they never had a realistic plan for systematically defeating the enemy army, and hoped futilely that war fatigue brought about by superior firepower would exhaust their enemy into capitulating. The Topography of Vietnam, which enabled VC forces to avoid direct attacks by withdrawing into and attacking from difficult terrain while also providing solid concealment from air bombardment, ultimately defeated such a lazy war strategy and aided the enemy in achieving carefully rehearsed goals, which through serious effort and slow but steady progress, lead to the fall of Saigon in 1975.


[1] http://www.haivenu-vietnam.com/vietnam-geography-topography.htm

[2] Mounted Combat in Vietnam. Department of the Army. http://www.history.army.mil/books/Vietnam/mounted/chapter1.htm#b3

[3] Berger, Carl, ed., The United States Air Force in Southeast Asia. Washington DC: Office of Air Force History, 1977, p. 366.

[4] http://www.historyplace.com/unitedstates/vietnam/index-1961.html

[5] Carland, John M., “Winning the Vietnam War: Westmoreland’s Approach in Two Documents”, The Journal of Military History, Vol. 68, No. 2., (Apr., 2004), pp. 553-574.

[6] See #2