However, regardless of the level of support from external sources, the success of the NLF movement depended overwhelmingly on its performance in combat. From a purely tactical point of view, of course, the NLF lost virtually every engagement to which it committed itself. Post-battle casualty counts, though usually confused by the Vietnamese practise of carrying dead and badly wounded off field, went overwhelmingly in the Americans' favour. U.S. forces often found that they could patrol enemy territory without being engaged. When the conflict is viewed not in terms of tactical victory or defeat, however, the NLF's strategic strengths become apparent: in a war of constant attrition, the guerrilla fighters were able to absorb heavy punishment as long as they inflicted noticeable damage on their enemy. The NLF's success was not due to any military prowess or astounding victory, for it had neither. It was achieved simply by keeping up a steady hammering of attacks while simultaneously refusing to be drawn out in any large numbers.
In keeping with this general doctrine, the NLF fought only where it knew it was strong. This meant that, just as Mao had realised in China more than two decades earlier, the rural areas were of primary importance. By 1964, the NLF had established considerable control over the countryside, levying taxes in 41 of the 44 provinces and operating in 80 percent of the area of South Vietnam. As has been established in Part I, this led to substantial political-ideological support, essential to the NLF throughout the conflict.
However, the NLF's actions in rural areas were not limited to political action. Whenever they entered these areas, Americans forces frequently found themselves under attack regardless of their immense technological superiority. The well-known NLF tactic - “Grasp the Belt of the GI and Fight Him” - was taken to a near-literal level, countering American fire superiority for the staggeringly straightforward reason that a commander could not call an artillery or air-strike on his own position. This aggressive tactic was used to great success on December 9th, 1964, when a group of guerrillas armed only with light infantry weapons attacked a U.S. amphibious tank group at such close quarters that “the heavy tank weapons could not be angled sharply to fire back”. That all fourteen tanks were destroyed is a testament to the effectiveness of the NLF's extreme approach to combat.
American technological superiority was similarly useless against the NLF's most basic weapon: the booby trap. From bodies wired with captured mines to camouflaged holes filled with sharpened bamboo sticks, booby traps accounted for one fifth of American wounds in South Vietnam. With such invisible danger all around, patrols made use of the sarcastically labelled (unofficial) tactic of “search and avoidance” just as often as they did search and destroy. The booby trap technique was also extremely cheap in resources, and helped to account for the fact that the NLF needed only about 60 tons per day to continue fighting, an impressive figure when compared with the 32,000 tons used by American forces.
To counter U.S. high explosives, frequently in the form of mines or air attack, NLF fighters created various ploys: they would send villagers to find suspicious objects and poke them with long sticks from behind bamboo shields; they would drag logs and chains to set off mines and foul sensor; they would, create false truck convoys with fake headlights; and they would construct dummy supply dumps and bridges. More than one thousand anti-aircraft weapons were deployed in-country, and camouflage was raised “to an art form.” In heavily bombed areas, the guerrillas simply dug tunnels that provided protection from anything but a direct hit, such that “One learned to feel very safe with a few feet of earth overhead during the bombing raids.” These tunnels were also extremely useful for launching undetected surprise attacks. An NLF manual explains that though “the enemy may be several times superior to us in strength and modern weapons,” the guerrillas still had the advantage “because we will launch surprise attacks from within the underground tunnels.” According to Village Chief Trinh Duc, the Cu Chi Tunnels around Saigon served as defence, as a trap for enemy troops, as a supply area, and as a staging area for recruits coming into the jungle from Saigon. The Cu Chi Tunnels were, as was discovered after the war, “an underground city,” and of vital importance to the NLF.
Even when tunnels were not available, the NLF was still highly competent in avoiding destruction. U.S. Major-General William DuPuy observed that when Vietcong losses were “too high…they just backed off and waited.” So elusive was the enemy that Brigadier General Willard Pearson wrote in a 1966 that “our biggest problem has been and remains one of target acquisition.” When by February of 1967 General Westmoreland's Operation Junction City began to threaten War Zone C, the COSVN withdrew into neighbouring Cambodia. Richard Stevens, an American engaged in combat in 1969-1970 in Quant Tri Province, writes cynically that “The NVA and VC almost always escaped on these operations, but we massacred multitudes of flora and fauna.” Frustrated reports, such as this one from the 1st Marine Corps Reconnaissance Battalion, were typical: “Called fire mission with unobserved results due to enemy movement into treeline, darkness, and terrain.” The NLF simply refused to fight on American terms, and was as a result able to remain active for the duration of the war.
