With most U.S. combat units slated to leave South Vietnam during 1970 and 1971, time was a critical factor for the success of Vietnamization and pacification. Neither program could thrive if Saigon's forces were distracted by enemy offensives launched from bases in Laos or Cambodia. U.S. artillery support during Operation Lam Son 719 While Abrams' logistical offensive temporarily reduced the level of enemy activity in the South, bases outside South Vietnam had been inviolable to allied ground forces. Harboring enemy forces, command facilities, and logistical depots, the Cambodian and Laotian bases threatened the fragile progress made in the South since Tet 1968. To the Nixon administration, Abrams' plans to violate the Communist sanctuaries had the special appeal of gaining more time for Vietnarnization and of compensating for the bombing halt over North Vietnam. Because of their proximity to Saigon, the bases in Cambodia received first priority. Planning for the cross-border attack occurred at a critical time in Cambodia. In early 1970 Cambodia's neutralist leader, Prince Norodom Sihanouk, was overthrown by his pro-Western Defense Minister, General Lon Nol. Among Lon Nol's first actions was closing the port of Sihanoukville to supplies destined for Communist forces in the border bases and in South Vietnam. He also demanded that Communist forces leave Cambodia and accepted Saigon's offer to apply pressure against those located near the border. A few weeks earlier, American B-52 bombers had begun in secret to bomb enemy bases in Cambodia. By late April, South Vietnamese military units, accompanied by American advisers, had mounted large-scale ground operations across the border. Cambodia On 1 May 1970, units of the 1st Cavalry Division, the 25th Infantry Division, and the 11th Armored Cavalry followed. Cambodia became a new battlefield of the Vietnam War. Cutting a broad swath through the enemy's Cambodian bases, Army units discovered large, sprawling, well-stocked storage sites, training camps, and hospitals, all recently occupied. What Americans did not find were large enemy forces or COSVN headquarters. Only small delaying forces offered sporadic resistance, while main force units retreated to northeastern Cambodia. Meanwhile the expansion of the war produced violent demonstrations in the United States. In response to the public outcry, Nixon imposed a geographical and time limit on operations in Cambodia, enabling the enemy to stay beyond reach. At the end of June, one day short of the sixty days allotted to the operation, all advisers accompanying the South Vietnamese and all U.S. Army units had left Cambodia. Political and military events in Cambodia triggered changes in the war as profound as those engendered by the Tet offensive. From a quiescent "sideshow" of the war, Cambodia became an arena for the major belligerents. Military activity increased in northern Cambodia and southern Laos as Hanoi established new infiltration routes and bases to replace those lost during the incursion. Hanoi made clear that it regarded all Indochina as a single theater of operations. Cambodia itself was engulfed in a virulent civil war. As U.S. Army units withdrew, the South Vietnamese Army found itself in a race against Communist forces to secure the Cambodian capital of Phnom Penh. Americans provided Saigon's overextended forces air and logistical support to enable them to stabilize the situation there. The time to strengthen Vietnamization gained by the incursion now had to be weighed in the balance against ARVN's new commitment in Cambodia. To the extent that South Vietnam's forces bolstered Lon Nol's regime, they were unable to contribute to pacification and rural security in their own country. Moreover, the South Vietnamese performance in Cambodia was mixed. When working closely with American advisers, the army acquitted itself well. But when forced to rely on its own resources, the army revealed its inexperience and limitations in attempting to plan and execute large operations. Despite ARVN's equivocal performance, less than a year later the Americans pressed the South Vietnamese to launch a second cross-border operation, this time into Laos. Although U.S. air, artillery, and logistical support would be provided, this time Army advisers would not accompany South Vietnamese forces. Laos The Americans' enthusiasm for the operation exceeded that of their allies. Anticipating high casualties, South Vietnam's leaders were reluctant to involve their army once more in extended operations outside their country. But American intelligence had detected a North Vietnamese build-up in the vicinity of Tchepone, a logistical center on the Ho Chi Minh Trail approximately 25 miles west of the South Vietnamese border in Laos. The Military Assistance Command regarded the build-up as a prelude to an NVA spring offensive in the northern provinces. Like the Cambodian incursion, the Laotian invasion was justified as benefiting Vietnamization, but with the added bonuses of spoiling a prospective offensive and cutting the Ho Chi Minh Trail. In preparation for the operation, Army helicopters and artillery were moved to the vicinity of the abandoned base at Khe Sanh. The 101st Airborne Division conducted a feint toward the A Shau valley to conceal the true objective. On 8 February 1971, spearheaded by tanks and with airmobile units leapfrogging ahead to establish fire support bases in Laos, a South Vietnamese mechanized column advanced down Highway 9 toward Tchepone. Operation LAM SON 719 had begun. The North Vietnamese were not deceived. South Vietnamese forces numbering about 25,000 became bogged down by heavy enemy resistance and bad weather. The drive toward Tchepone stalled. Facing the South Vietnamese were elements of five NVA divisions, as well as a tank regiment, an artillery regiment, and at least nineteen antiaircraft battalions. After a delay of several days, South Vietnamese forces air-assaulted into the heavily bombed town of Tchepone. By that time, the North Vietnamese had counterattacked with Soviet- built T54 and T55 tanks, heavy artillery, and infantry. They struck the rear of the South Vietnamese forces strung out on Highway 9, blocking their main avenue of withdrawal. Enemy forces al overwhelmed several South Vietnamese fire support bases, depriving ARV units of desperately needed flank protection. The South Vietnamese al o lacked antitank weapons to counter the North Vietnamese armor that appeared on the Laotian )ungle trails. The result was near-disaster. Army helicopter pilots trying to rescue South Vietnamese soldiers from their besieged hilltop fire bases encountered intense antiaircraft fire. Panic ensued when some South Vietnamese units ran out of ammunition. In some units, all semblance of an orderly withdrawal vanished as desperate South Vietnamese soldiers pushed the wounded off evacuation helicopters or clung to helicopter skids to reach safety. Eventually, ARVN forces punched their way out of Laos, but only after paying a heavy price. That the South Vietnamese Army had reached its objective of Tchepone was of little consequence. Its stay there was brief and the supply caches it discovered disappointingly small. Saigon's forces had failed to sever the Ho Chi Minh Trail; infiltration reportedly increased during LAM SON 719, as the North Vietnamese shifted traffic to roads and trails further to the west in Laos. In addition to losing nearly 2,000 men, the South Vietnamese lost large amounts of equipment during their disorderly withdrawal, and the U.S. Army lost 107 helicopters, the highest number in any one operation of the war. Supporters pointed to heavy enemy casualties and argued that equipment losses were reasonable, given the large number of helicopters used to support LAM SON 719. The battle nevertheless raised disturbing questions among Army officials about the vulnerability of helicopters in mid- or high-intensity conflict. What was the future of airmobility in any war where the enemy possessed a significant antiaircraft capability? LAM SON 719 proved to be a less ambiguous test of Vietnamization than the Cambodian incursion. The South Vietnamese Army did not perform well in Laos. Reflecting on the operation, General Ngo Quan Truong, the commander of I Corps, noted ARVN's chronic weakness in planning for and co-ordinating combat support. He also noted that from the battalion to the division level, the army had become dependent on U.S. advisers. At the highest levels of command, he added, "the need for advisers was more acutely felt in two specific areas: planning and leadership. The basic weakness of ARVN units at regimental and sometimes division level in those areas," he continued, "seriously affected the performance of subordinate units." LAM SON 719 scored one success, forestalling a Communist spring offensive in the northern provinces; in other respects, it was a failure and an ill omen for the future. Back to Table of Contents -- US Army in Vietnam Back to Vietnam Military History List of Issues Back to MagWeb Magazine List © Copyright 2004 by Coalition Web, Inc. This article appears in MagWeb.com (Magazine Web) on the Internet World Wide Web. Other articles from military history and related magazines are available at http://www.magweb.com