The Easter Halt

Sept. 1, 1998

The year 1972 produced notable US battlefield victories in Vietnam, most of which, however, now are virtually forgotten. The American military managed to prevail in these struggles despite serious weakness caused by the US exodus from Southeast Asia. The 1972 battles marked the final major US engagements of the Vietnam War. Moreover, they illumined the future of the Air Force more than anyone imagined at the time.

Spring 1972 saw an onslaught of regular North Vietnamese units into South Vietnam, with Hanoi hoping to deliver a knockout punch to end its long war of conquest in the South. US politics had put the Air Force in the position of having to compensate for drastic reductions of ground forces. Faced with this challenge, USAF responded with a mass movement of troops and equipment and fearsome attacks with new systems, all of which were key factors in halting the invasion.

North Vietnam’s patient and practical leaders had for several years observed the steady decline in American strength in the South. Then, on Good Friday, March 30, 1972, the Communists struck, launching a series of military drives collectively known as the “Easter Offensive.”

Hanoi sought an outright military victory in order to establish Communist control over South Vietnam, drive US forces from the South, and prevent the re-election of President Richard Nixon. They called the action the “Nguyen Hue Offensive” in honor of a Vietnamese hero who had inflicted a massive defeat on Chinese forces in 1789.

Hanoi’s desire for a military victory was understandable; the North Vietnamese had been fighting for decades, and a clear-cut triumph on the battlefield would be far more satisfying than one won at the negotiating table in Paris. Moreover, Communist strategy might have had a personal edge to it: The architect of the offensive was Gen. Vo Nguyen Giap, whose questionable tactics in the Battle of Khe Sanh and the Tet Offensive in 1968 ended in bloody debacles costing North Vietnam some 100,000 casualties.

In the Soviet Image

These events vitiated Communist offensive capabilities for almost four years, but Giap rebuilt his forces. He created a new kind of North Vietnamese army built in the Soviet image-that is, well equipped with tanks, artillery, and, most importantly, an anti-aircraft system that could be taken into the field.

The Easter Offensive was a massive conventional attack. Giap committed to the battles 14 regular divisions, 26 regiments, and a massive amount of supporting armor-more than 600 T-54, T-55, and the amphibious PT-76 tanks. By comparison, the German Army launched the Battle of the Ardennes with 19 divisions and 950 tanks. The North Vietnamese ground forces also were fully equipped with artillery, including the dangerous and effective 130 mm and 152 mm artillery pieces and huge 160 mm mortars.

Even so, the key element of Giap’s arsenal was a vastly expanded anti-aircraft system that traveled along with invading forces. The flak weapons included 23, 37, 57, 85, and 100 mm guns. Supplementing the familiar SA-2 surface-to-air missiles were deadly man-portable SA-7 Strela heat-seeking missiles, for which totally new tactics had to be devised.

On the eve of the Easter Offensive, Giap’s confidence in his ability to gain military victory was high, but not unreasonably so, given the great decline in the number of American ground forces in South Vietnam. The US land component had shrunk from 550,000 troops at the height of the war in 1969 to only 95,000. During the same period, the strength of US air and naval forces fell to about one-third of their previous peak levels.

This across-the-board decline in power reflected the American policy of Vietnamization and disengagement. The United States wished to negotiate a face-saving settlement with North Vietnam that would permit withdrawal of all ground forces. At the same time it sought to arm and train South Vietnamese forces so that they could defend their country against the North.

This policy was pursued in the context of the so-called Nixon Doctrine, which stated that the United States would provide military aid to Asian countries under Communist assault. The aid would include air and naval forces if required but would under no circumstances involve US ground forces-a reversal of policies advocated for so long by President Lyndon B. Johnson and Secretary of Defense Robert S. McNamara.

Unfortunately, there was a fatal flaw in Vietnamization. South Vietnamese forces were trained in the American style of war in which, whenever possible, US planners would use overwhelming airpower to destroy enemy resistance before sending in US ground forces for battle. Though strengthened in recent years, South Vietnam’s air force (VNAF) was too small to provide such support. It did not have the correct training and equipment. Moreover, it lacked helicopters and the transports to provide the air-mobile forces and prompt, generous air resupply to which the South Vietnamese Army had become accustomed.

Because these elements were lacking, only the best-led units of the South Vietnamese army (ARVN) were capable of resisting the Communist assault. The quality of ARVN leadership varied and was often dependent upon the extent and expertise of US advisors still in the field.

Tactical Surprise

In the months before Easter 1972, the Communist buildup had been noted, but Washington and Saigon underestimated the scope, magnitude, and character of the coming attack. Thus, the North Vietnamese achieved considerable tactical surprise. Hanoi’s invading forces thrust into three of South Vietnam’s four military regions. (See map at right.) Just as Hitler had used clouds and low ceilings to mask the advance of German armor in the Battle of the Bulge, so did Giap count on bad weather hampering USAF reconnaissance and air strikes.

In Military Region I, more than 40,000 North Vietnamese troops swarmed southward through the DMZ and eastward from camps in Laos. By April 2, the enemy had captured all intervening fire-support bases and was moving directly on Quang Tri City, the provincial capital. Interdiction by US Air Force fighter-bombers and B-52 bombers slowed the advance, but Quang Tri City was evacuated May 1. The enemy then reorganized for a drive on Hue.

In Military Region II, 20,000 Communist soldiers surged out of Laotian and Cambodian sanctuaries to attack the major cities of Kontum and Pleiku. The intent was to cut Pleiku off, then drive on to split South Vietnam in half. South Vietnamese troops fought well, stiffened by US advisors. Kontum, however, was cut off and surrounded. The city was sustained by a massive aerial resupply effort. In addition, the Communist military attack failed. US Air Force B-52s and tactical fighters combined with TOW­toting US Army UH-1s to defeat the northern invaders in the field, despite a monumental effort by huge numbers of North Vietnamese tanks and artillery.

In Military Region III, one regular North Vietnamese division and two Viet Cong divisions-some 30,000 men combined-sallied from their Cambodian salient to attack An Loc and Loc Ninh in hopes that a quick victory would lead to a drive down Highway 13 to Saigon itself.

The Easter Offensive engaged the full weight of USAF’s in-theater forces which, though much reduced, were still formidable. The B-52 force, which had proved to be key in the relief of Khe Sanh four years earlier, had been reinforced. There were 53 of the heavy bombers at U Tapao RTAB, Thailand, and 85 at Andersen AFB, Guam. By the end of May, another 33 BUFFs were deployed against the attackers, bringing the force total to 171 B-52s.

Despite three years of Vietnamization, some 102 Air Force fighters remained in South Vietnam–64 F-4s, 15 A-1s, and 23 A-37s. These were supplemented by 15 AC-119 gunships. Also on hand outside of South Vietnam were 91 F-4s and 16 F-105 fighters, 10 B-57s, and 13 AC-130 gunships based in Thailand. (An AC-130 would fall victim to a Strela, the first loss of its type.)

Desperate Situations

These forces were committed as soon as weather permitted. The combination of Tactical Air Control Systems, Forward Air Controllers, radar, and airborne command posts enabled American commanders to get the maximum effectiveness from the limited resources. B-52 bomber and tactical fighter attacks were provided in the most desperate situations as they arose, and gunships were allocated to the outposts under the heaviest fire. The gunships also provided mobile cover for retreating forces, laying down gunfire as roadblocks to the pursuing enemy armor.

While the in-theater forces were putting on a maximum effort, the orders went out for a worldwide mobilization of USAF units to return to Southeast Asia prepared to fight a vicious, protracted battle. The transfer of B-52s was called “Bullet Shot.” The return of tactical fighters went by the name “Constant Guard” (I-IV).

The 45 days following the start of the Easter Offensive saw the Air Force demonstrate global mobility and power on a massive scale. From bases in Korea, the Philippines, and the United States, additional fighters, bombers, gunships, electronic warfare birds, search and rescue units, transports, and tankers moved in a swift, smooth flow to Southeast Asia. In some instances, units were in combat just three days after they received orders to move.

The strike forces built up rapidly: Fighters doubled to almost 400, B-52 bomber strength increased to 171, and the number of tankers rose to 168. The Navy and Marines also responded, with the carrier force building to six.

In many instances, USAF’s airmen were coming back for their second or third tours in the area, often to the same bases from which they had operated previously. The bases themselves were in varying states of readiness; after the years-long drawdown, the local population had stripped them of useful material, from radar gear down to household wiring, toilets, and window panes.

Air Force units returned to find runways intact, but not much else on hand, and tent cities sprouted where there had once been a complete base complex that had included air-conditioned hootches, clubs, theaters, and swimming pools.

Creature comforts were of little consequence, however, as the new units were immediately thrown into desperate battle. B-52 sorties in South Vietnam built from 689 in March to 2,223 in May. Fighter strike sorties of all branches (including the South Vietnamese air force) rose from 4,237 in March to 18,444 in May and were held at 15,951 in June.

USAF suffered heavy casualties. Between the start of the offensive and its withering away in June, the Air Force lost 77 aircraft, including 34 F-4 Phantoms. The scope of the conflict had been expanded on May 8 when Nixon authorized extensive strikes into North Vietnam itself under the code name Operation Linebacker. As it turned out, Nixon’s decision to take the war north was crucial, because North Vietnam, as a result, could never muster the kind of logistical flow necessary to support such an intense offensive.

USAF and the Halt Phase

The relative degree of Air Force responsibility for halting the invasion varied from region to region and depended in large part upon the effectiveness of the South Vietnamese army in defending its homeland. Where the ARVN fought effectively, as it did in Military Region II, the demands on USAF, while still crucial, were moderate. Where events or poor leadership caused ARVN to waver, as in Military Region I, massive USAF intervention was absolutely essential.

Yet in every region, the same combination of USAF capabilities worked effectively. Massive B-52 strikes (some by aircraft that were in the United States only 72 hours earlier) hammered Communist troop concentrations, while tactical aircraft carried out surgical strikes at specific targets. Tankers once again became the true force multipliers, refueling both bombers and fighters. At bases such as Bien Hoa in South Vietnam, “turn-around” tactics permitted fighters from Thailand to land, rearm, and make another sortie before returning to home base.

Significantly, the Air Force made use of “smart bombs” against key targets. Cargo aircraft weaved their way through smoke, flak, and the dangerous Strela missiles to land when they could or drop when they could not. Gunships flew protective sorties around embattled garrisons, laying down a curtain of fire to suppress enemy attacks. Amidst the carnage, FACs flew calmly, calling out targets and monitoring enemy movements. And through it all, the search and rescue units worked to recover downed airmen.

The bottom line was that, in under two months, USAF had returned to Southeast Asia-in strength and fully proficient-and went on to break up and halt Giap’s powerful offensive and thereby thwart Hanoi’s drive to take over South Vietnam.

Of the three major invasion thrusts, the stakes had been greatest in Military Region III where a decisive North Vietnamese drive past An Loc and into Saigon might well have won the war in a single battle. The fight for MR III typifies the struggle that unfolded in all three areas and can be used as a model to illustrate the powerful results achieved by USAF in all three regions. The strength of the Air Force effort was heightened by its use of battle-proven techniques.

The enemy had brushed by weak ARVN resistance to put the town of An Loc under a siege that would last for two months and would become a byword for hardship and misery. The ARVN units invested at An Loc had no artillery with which they could respond to the almost continuous shelling of the city. The South Vietnamese army depended entirely upon aircraft for critical supplies.

Burning Hulks

Continuous sorties by B-52 bombers, using “Bugle Note” tactics that had been so effective at Khe Sanh in 1968, smashed the enemy buildup and made North Vietnamese commanders spread out their force, inhibiting their ability to concentrate for an attack. US Air Force FACs flew through the intense anti-aircraft fire to spot artillery, mortar, and rocket batteries and call in strikes by the fighter-bombers. When the enemy, using tanks and infantry, surged past the city’s outer fortifications into the heart of An Loc’s defenses, the F-4s and gunships ground them down with a series of ferocious attacks that left the tanks destroyed in the streets.

Just as at Khe Sanh, Allied air forces operated in two modes. On the one hand, they were at the front lines, blunting attacks with bombs and rockets. On the other, they placed the besieging Communist forces under siege themselves by bombing supply dumps and routes.

The demand for aerial resupply was crucial in the battle for An Loc, where more than 20,000 personnel required everything to be brought in by air. South Vietnamese air force efforts at resupply had failed, for the anti-aircraft fire was too intense. Their aerial drops had been inaccurate. Initial USAF resupply efforts were both ineffective and costly. The C-130s began Container Delivery System drops immediately, but these were too hazardous. Intense anti-aircraft fire had brought down one C-130 and caused heavy damage to four others.

The C-130 crews turned to a Ground Radar Aerial Delivery System, but a series of parachute malfunctions aborted the effort. Knowing that the defenders at An Loc were desperate for food and ammunition, the CDS operations were resumed with some success until another C-130 was shot down. Night CDS drops were tried but proved unsuccessful. It was impossible to deliver the supplies to the drop zone with any accuracy.

The supply situation was finally resolved with the resumption of GRADS sorties, this time with an improved parachute system. The difference was remarkable, and about 1,000 tons of supplies per day were dropped to the defenders. (At Kontum, in MR II, the All Weather Air Delivery System had been the delivery system of choice.)

The massive weight of the American aerial effort finally paid off in the field; North Vietnamese forces suffered enormous casualties and were forced to withdraw in all three military regions. South Vietnamese forces were able to recapture their badly damaged cities.

In retrospect, it becomes clear that the American air assaults of spring 1972 bought South Vietnam three more years of existence. The United States in December 1972 forced Hanoi to resume serious peace negotiations by unleashing Linebacker II, 11 days of heavy bombing of key targets in the North. At the end of it, the North Vietnamese had had enough for a while. In February 1973, the warring parties signed the Paris peace accords, and American POWs returned home.

Giap, after suffering a third major battlefield fiasco, licked his wounds and waited for the right time to attack again. It came in spring 1975, when American forces had withdrawn, Nixon was no longer in the White House, and it was clear the American public no longer had the will to defend South Vietnam. Then, he attacked, and this time, without US backing, South Vietnamese military units offered scant resistance. Communist tanks finally rolled into Saigon on April 30, 1975. American airpower had been withheld, and Giap had his victory at last.

Walter J. Boyne, former director of the National Air and Space Museum in Washington, is a retired Air Force colonel and author. He has written more than 400 articles about aviation topics and 28 books, the most recent of which is Beyond the Wild Blue: A History of the United States Air Force, 1947-1997. His most recent article for Air Force Magazine, “Airpower at Khe Sanh,” appeared in the August 1998 issue.