The Military History Thread

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February 8, 1971
Operation Lam Son 719

By late 1970, there were increasing signs of heavy Communist activity in southeastern Laos, activity which heralded a North Vietnamese offensive. This build-up was alarming to both Washington and the American command, and prompted a spoiling attack to derail future communist objectives. This would involve an attack toward the Ho Chi Minh Trail. A success here would not only delay any enemy offensives, but create supply shortages that would be felt in 12-18 months just as the last US troops were leaving South Vietnam. It was also hoped to test the progress of “Vietnamization”, the turning over of main operations to the ARVN.

On January 7, 1971, General Abrams was authorized to begin detailed planning for an attack against NVA Base Areas 604 and 611. US operations would be hampered by the recently passed Cooper-Church Amendment, prohibiting US ground forces from entering Laos. Therefore, the American portion of the campaign, code-named Dewey Canyon II, would be limited to a preliminary drive along Route 9 to Khe Sanh to clear the route to the Laotian border and reestablish Khe Sanh as the main base for the next phase. This phase, Lam Son 719, would involve an ARVN armored/infantry attack along Route 9 toward the Laotian town of Tchepone, the perceived nexus of Base Area 604. This advance would be protected by a series of leapfrogging aerial infantry assaults to cover the flanks of the main column. After operations against the Base Areas, the force would retire back through the A Shau Valley. It was hoped that the force could remain in Laos until the rainy season was underway at the beginning of May.

Due to the notoriously poor ARVN security, planning was rushed. Individual units did not learn about their planned participation until January 17. The Airborne Division that was to lead the operation received no detailed plans until February 2. At the lower levels, it was limited to the intelligence and operational staffs of ARVN I Corps (Lt-Gen. Hoang Xuan Lam, who was to command the operation), and US XXIV Corps. When Lam was finally briefed in Saigon, his chief of operations was forbidden to attend the meeting, even though he had helped to write the very plan under discussion. Lam’s operational area was restricted to a corridor no wider than 15 miles on either side of Route 9 and a penetration no deeper than Tchepone. Command, control, and coordination were going to be problematic. Lt-Gen. Le Nguyen Khang, the Vietnamese Marine Corps commander and protégé of Vice President Nguyen Cao Ky, whose troops were scheduled to participate, actually outranked Lam, who had the support of President Nguyen Van Thieu. The same applied to Lt.-Gen. Du Quoc Dong, commander of ARVN Airborne forces also scheduled to participate.

Dewey Canyon II got underway on January 30. 1st Brigade, 5th Infantry Division (Mechanized), with engineer and armor support drove for Khe Sanh against sketchy resistance, while 101st Airborne Division feinted into the A Shau Valley. By February 5, Route 9 had been secured up to the Laotian border. However, poor weather and obstacles pushed the rehabilitation of the airstrip a week behind schedule. A completely new airstrip had to be built and the first aircraft arrived on February 15.

By early 1971, North Vietnamese troop strength in the Base Area 604 area was estimated at 22,000 men: 7000 combat troops, 10,000 logistical and support personnel, and 5000 Pathet Lao, all under the command of the newly created B-70 Corps. The North Vietnamese were expecting some sort of operation as early as January 26, when the text of an intercepted radio message read “It has been determined that the enemy may strike into our cargo carrier system in order to cut it off.”

Tactical air strikes that were to precede the invasion and suppress AA positions were suspended due to poor flying weather. The land incursion began on February 8, with an attack along Route 9, airborne units covering the flanks. Two ranger battalions were helilifted into outposts that would serve as tripwires for any Communist advance into the incursion area. The mission of the central column was to advance down the valley of the Se Pone River, a relatively flat area of brush interspersed with patches of jungle and dominated by heights to its north and the river and more mountains to the south. Almost immediately, supporting helicopters began to take fire from the heights. Making matters worse, Route 9 was in poor condition, so poor in fact that only tracked vehicles and jeeps could make the westward journey. This threw the burden of reinforcement and resupply onto the aviation assets, a role that was made increasingly more dangerous due to low cloud cover and incessant AA fire.

The armored task force secured Route 9 all the way to Ban Dong, approximately halfway to Tchepone. By February 11, Ban Dong had become the central fire base and command center for the operation. Here the South Vietnamese forces stalled while awaiting orders from Gen. Lam. 2 days later, Abrams and Sutherland flew to Lam’s forward command post in order to speed up the timetable. At the meeting of the generals, it was instead decided to extend the 1st Division's line of outposts south of Route 9 westward to cover the projected advance. This would take an additional 5 days.

The North Vietnamese response to the incursion was gradual due to a US naval diversion off the North Vietnamese coast, but this did not last long. B-70 Corps commanded 3 divisions in the incursion area, the 304th, 308th and 320th. The 2nd Division had also moved up from the south to the Tchepone area and then began to move east to meet the ARVN threat. By early March, Hanoi had massed 36,000 troops in the area, outnumbering the South Vietnamese force by 2-1. The NVA plan was to first isolate the firebases with AA fire. The outposts would then be pounded by round-the-clock mortar, artillery, and rocket fire. Although the firebases were themselves equipped with artillery, their guns were quickly outranged by the NVA’s 122mm and 130mm pieces. Massed ground attacks, supported by artillery and armor would then finish the job.

On February 19, elements of 308th Division attacked the ranger outposts, which were overrun by the end of the 21st, the survivors fighting their way back to FSB 30. FSB Hotel 2, south of Route 9, and FSB 31 followed, manned by elements of the ARVN Airborne Division. Division commander Gen. Dong had opposed stationing his elite paratroopers in static defensive positions and felt that his men’s usual aggressiveness had been stifled. Vicious AA fire made reinforcement and resupply of the firebase impossible. An armored relief force never arrived, due to conflicting orders from Lam and Dong. The base fell on February 25.

While the main South Vietnamese column stalled at Ban Dong and the Ranger and Airborne elements were fighting for their lives, President Thieu and Gen. Lam decided to launch a face-saving airborne assault on Tchepone itself. If South Vietnamese forces could at least occupy Tchepone, Thieu would have a political excuse for declaring victory and withdrawing his forces. The decision was made to make the assault not with the armored task force, but with elements of 1st Division. That meant that the occupation of the firebases south of Route 9 had to be taken over by Marine Corps forces, which lost even more valuable time.

The assault began on March 3, when elements of 1st Division were helilifted into 2 firebases (Lolo and Sophia) and LZ Liz, all south of Route 9. 3 days later, 2nd and 3rd Battalions of 2nd Regiment were lifted from Khe Sanh to Tchepone (LZ Hope) by 276 UH-1s, the largest helicopter assault of the Vietnam War. For 2 days the two battalions searched Tchepone and the immediate vicinity, but found little but the bodies of NVA soldiers killed by air strikes. The NVA responded by increasing its daily artillery bombardments of the firebases. Their goal in Laos seemingly achieved, Thieu and Lam ordered a withdrawal beginning on March 9 that was to continue through the rest of the month, destroying Base Area 604 and any supplies discovered in their path. Gen. Abrams implored Thieu to reinforce the troops in Laos and keep disrupting the area until the beginning of the rainy season.

The battle was shifting to Hanoi’s advantage. AA fire remained devastating and the NVA had no trouble resupplying or reinforcing their troops. As soon as it became evident that ARVN forces had begun a withdrawal, the NVA increased its efforts to destroy these forces before they could reach South Vietnam. The undermanned firebases were attacked, and ARVN ground forces had to run a gauntlet of ambushes along Route 9. The retreat quickly devolved into a rout. One by one the isolated firebases were closed out or overrun and each withdrawal was costly. By March 25th, the South Vietnamese force that had survived had left Laos behind. The forward base at Khe Sanh had also come under increasing bombardment and sapper attacks and by April 6 it was abandoned and Operation Lam Son 719 was over.

Thieu made extravagant claims of success, but, although Lam Son 719 had set back North Vietnamese logistical operations in southeastern Laos, truck traffic on the trail system increased immediately after the conclusion of the operation. The American command’s claims of success were more limited in scope: MACV claimed that 88 NVA tanks had been destroyed during the operation, 59 by tactical air power. It also fully understood that the operation had exposed grave deficiencies in South Vietnamese “planning, organization, leadership, motivation, and operational expertise.”

For the North Vietnamese, the Route 9 - Southern Laos Victory was viewed as a complete success. The military expansion of the Ho Chi Minh Trail which had begun in 1970 at the expense of Laotian forces, was quickly accelerated. Laotian troops were soon withdrawing toward the Mekong River and a logistical artery 60 miles wide was soon expanded to 90 miles. Another result of the operation was a firm decision by the Politburo to launch a major conventional invasion of South Vietnam in early 1972, paving the way for the Easter Offensive.