Until the twentieth century, artillery was almost the sole source of battlefield firepower. During the Vietnam War firepower support also came from (Army) helicopters and (Air Force, Navy, and Marine) tactical aircraft. Each system had its advantages, which compensated for the disadvantages of the others. Artillery is accurate, responsive, and flexible; helicopters offer precision and direct observation; and close air support is highly destructive. The challenge for ground commanders was to integrate these forms of firepower with the scheme of maneuver to produce the desired tactical effect.
Most field artillery units had a mission of either direct support (DS) or general support (GS). A division normally had one DS artillery battalion for each maneuver brigade, plus a GS battalion to provide fires for the whole division. Nondivisional artillery units were organized into artillery groups, which had a mission of providing general support to an entire corps (called "field forces" in Vietnam). For some specific operations, nondivisional artillery could be given the mission of reinforcing (r) the fires of a divisional unit. In the absence of large divisional operations in Vietnam, most nondivisional artillery units were used to provide support for a specific geographical area.
When supporting a brigade, the DS artillery battalion normally had three firing batteries of six guns each. In conventional operations this would mean there was one artillery battery to support each maneuver company-although the firing batteries remained under the control of the artillery battalion to provide massed fires across the brigade sector. In Vietnam, however, operations tended to be fragmented and dispersed, and the guns had to disperse in order to support them. This was a violation of the time-proven principle that artillery is effective only when fired in mass, but during the Vietnam War the enemy rarely presented massed targets for Allied artillery.
Starting at the company level, every echelon in the maneuver chain of command had a fire support coordinator (FISCOORD). The company FISCOORD was the company commander, but he was assisted in this task by a forward observer (FO) from the DS artillery battalion. FOs generally were the most junior lieutenants in the artillery. Nonetheless, good FOs were highly prized by their infantry units, and a company commander usually kept his FO within arm's reach. The enemy also appreciated the extra combat power the FO represented and made special efforts to identify and kill him quickly if possible.
At the maneuver battalion, the FISCOORD was the artillery liaison officer (LNO), a more senior captain also supplied by the DS artillery battalion. Quite often, the artillery LNO worked from a command and control (C²) helicopter, along with the supported maneuver battalion commander and his operations officer (S-3). The LNO was responsible for coordinating all fires for the battalion, not just artillery-delivered fires. Thus, the LNO had to ensure that artillery, helicopters, and tactical air were synchronized on the target, yet separated from each other in time and space to preclude midair collisions. Making the task more complicated, radios in Army and Air Force strike aircraft were incompatible. Operating a bank of radios in the C² helicopter, the LNO had to pass messages and commands back and forth between FOs on the ground, Army helicopters in the air, and Air Force forward air controllers (FACs) on the ground or in the air-who then talked to the Air Force aircraft.
The commander of the DS artillery battalion was the designated FISCOORD for the brigade, and the division artillery (DIVARTY) commander was the FISCOORD for the division. In practice, assistant FISCOORDs at the brigade and division fire support coordination centers (FSCCs) performed the day-to-day tasks.
When a company FO called for fire on the radio, his request went directly to either the battery or battalion (depending on the situation) fire direction center (FDC). The LNO at the maneuver battalion monitored the call and had the authority to cancel or modify the request. If the LNO failed to intervene, his silence implied consent and the mission continued. The fire direction officer (FDO) made the final determination and issued the fire order. The FDC crew then computed the data and sent the fire commands to the gun crews.
Most FDCs in Vietnam, especially in the later years, were equipped with FADAC, the U.S. Army's first digital fire direction computer. "Freddy" FADAC, however, was a notoriously cranky piece of equipment and was often inoperable for one reason or another. It also was slow, requiring two-thirds of the projectile time of flight for an initial solution. A well-trained FDC using manual charts and graphical computational tools could beat FADAC every time. Where Freddy excelled was in handling multiple fire missions simultaneously.
Artillery was (and still is) the fastest of the fire support means. Under ideal conditions, a well-trained battery had the technical capability of placing rounds on the target within two to three minutes of the FO's initial request. Combat conditions are never ideal, however, and in Vietnam, the actual average was something more like 6 minutes for light artillery and 13 minutes for heavy guns, which often had to shift their trails to fire. Even longer delays were caused by the political nature of the war itself. In populated areas, the local Vietnamese sector headquarters had to approve the mission before it could be fired. Later in the war, Air Warning Control Centers (AWCCs) were established to broadcast warnings to all friendly aircraft in the area. This added another element of delay. Despite these delays, artillery was still much more responsive than tactical air, which took anywhere from 40 minutes to an hour from the initial call to target attack.
A revolutionary war like Vietnam warped the traditional relationships between firepower and maneuver in subtle ways. On the strategic level, the front line of the war may have been the DMZ and the Cambodian border, but on the operational and tactical levels there were no front lines. Instead of being linear, the war was circular. The enemy was capable of being anywhere "out there." This, combined with the dense jungle in which actions were fought, reduced the effectiveness of envelopments, turning movements, and the other classical forms of tactical maneuver. Company commanders quickly learned that adding more friendly infantry to a fight quite often led to more friendly casualties.
Concern over friendly casualties was another factor inhibiting maneuver in Vietnam. More than any other war in American history, the preservation of soldiers' lives was the overriding tactical imperative. This was driven by the very shaky political support for the war at home, combined with the close scrutiny and almost immediate (and sometimes inaccurate) media coverage. The war had no clearly defined objectives, and no clearly articulated national interests were at stake. Faced with these tactical, social, and political imperatives, the only alternate course of action was to use firepower in massive quantities and to give it primacy over maneuver. The prevailing philosophy became "bullets, not bodies." The United States, of course, with its abundant materiel resources, could do this easily. But in so doing, it provided the worst sort of role model for the Army of the Republic of Vietnam (ARVN), which did not have the resources but knew no other way of operating once it had to fight on its own. Thus, infantry units in Vietnam maneuvered to achieve two objectives: first to find the enemy, and then to take up the best position from which to call in and direct overwhelming fire assets to finish the job. The automatic response to bring in heavy firepower meant that infantry units had to stay at least 200 to 300 meters away from the enemy to avoid becoming casualties of their own supporting fires. The Viet Cong (VC) and People's Army of Vietnam (PAVN) quickly recognized this weakness and developed "hugging tactics," which brought them in so close that Allied firepower became unusable.
Some U.S. commanders decried the overdependence on firepower and the corresponding loss of infantry maneuver skills. They advocated the adoption of the same guerrilla tactics used by the VC and PAVN. But even these minority voices recognized that U.S. firepower was the final trump card. As Lieutenant Colonel David Hackworth said of his experiences with the 9th Infantry Division's 4th Battalion, 39th Infantry: "Only guerrilla tactics augmented by U.S. firepower can defeat the enemy at low cost."
Of all the forms of Allied operations, the VC and PAVN most feared the cordon. This operation normally began with multiple helicopter assault landings to isolate and encircle an enemy unit in its base camp. Once on the ground, Allied troops formed a perimeter with a radius of 500 to 1,000 meters. When the cordon was sealed, everything inside was systematically pounded with air and artillery firepower. This was both slow and methodical to avoid casualties from friendly fire. It became even more careful as infantry moved in toward the center, shrinking the circle and the target area. The slowly moving infantry always carefully marked their positions well to avoid taking friendly fire. If set up properly and sprung quickly, cordon operations were very effective.
Earlier in the war, fire bases were little more than temporary artillery emplacements established to support infantry operating in a given area. They were set up quickly, usually by air, and abandoned just as quickly. But then the Communist forces drastically scaled back operations after suffering a crushing tactical defeat in the 1968 Têt Offensive. The Allies responded by using fire bases as a means to lure the enemy into firepower traps. Fire bases thus became semipermanent fortresses with dug-in gun pits, bunkers, and up to 25,000 sandbags for a single battery.
This basically was the same tactic the French had tried, and they failed with it on a grand scale at Dienbienphu. For the Americans, it was a success-on the tactical level at least-because they had both the artillery and air assets to overwhelmingly reinforce any fire base that came under attack. One result of this approach was that many infantry units were reduced to little more than perimeter security guards for the fire bases. Another result was that American artillery positions routinely came under direct ground attack more than at any other time since the Civil War, when artillery was still a direct fire weapon. Artillerymen devised many innovative ways to defend themselves, including the flechette-firing "Beehive" round and "Killer Junior," a high-explosive round with a time fuze set to detonate 30 feet off the ground at ranges between 200 and 1,000 meters. Communist forces never managed to overrun a single American fire base.
Operating from fire bases required new ways of thinking for American artillerymen. In conventional operations the guns of a battery usually were positioned in a staggered line parallel to the infantry front line, 2,000 or 3,000 meters to the front. In Vietnam the "front" was in all directions, and only 50 or 100 meters away. The solution was to position the guns on a fire base in either a diamond (four-gun battery) or a star (six-gun battery) formation. That way the guns could fire in any direction and the pattern of rounds (called a "sheaf") impacting on the ground would be the same. Setting up to fire in all directions also required special preparations in the gun pits and modifications to the firing charts in the FDC.
The fire base concept led to a sharp increase in one particularly worthless form of artillery fire. Harassment and interdiction (H&I) fire consisted of random rounds fired at "suspected and likely" enemy locations and routes. H&I was usually fired at night and was unobserved. It became slightly more effective later in the war with the introduction of sophisticated remote sensors, which served as firing cues. In general, however, H&I fire was largely a waste of ammunition, accounting for some 60 percent of all artillery fire during the war. In fact, only about fifteen percent of all artillery rounds fired were in support of troops in contact.
From a purely "systems analysis" standpoint, artillery fire in Vietnam was rather ineffective. According to the most optimistic estimates, it took well over 1,000 rounds to kill a single enemy soldier. But these results were no different than in other wars. Artillery is effective only when used in conjunction with maneuver to produce a synergistic effect. Artillery, in fact, is most effective when used to neutralize (rather than destroy) an enemy force while friendly maneuver units gain overwhelming positional advantage for the final kill.
This, of course, did not happen during the Vietnam War. Early in the war, U.S. policymakers opted for a war of attrition based in part on an imperfect understanding and unrealistic expectations of the ability of American firepower to send a persuasive message. The Communist forces never did crack, despite the ever-increasing levels of destruction. In the end it came down to a classic Clauswitzian test of wills and national resolve.
Robert H. Scales, Jr. best summarized the principal firepower lesson of the Vietnam War: "If a single lesson is to be learned from the example of Vietnam it is that a finite limit exists to what modern firepower can achieve in limited war, no matter how sophisticated the ordnance or how intelligently it is applied. Overwhelming firepower cannot compensate for bad strategy." David T. Zabecki
Bailey, Jonathan B. A. Field Artillery and Firepower. Oxford, UK: Military Press, 1987.; Ott, David E. Field Artillery, 1954-1973. Washington, DC: Office of the Chief of Military History, Vietnam Studies, 1975.; Scales, Robert H., Jr. Firepower in Limited War. 2nd ed. Novato, CA: Presidio Press, 1995.; U.S. Department of the Army. FM 6-40 Field Artillery Cannon Gunnery. Washington, DC: U.S. Government Printing Office, 1967.
David T. Zabecki