Between 1959 and 1970, the Ho Chi Minh Trail had become the key logistical artery for the PAVN/VC, in their effort to conduct military operations to topple the U.S.-supported government of South Vietnam and create a unified nation.

One U.S. intelligence report estimated that 90 percent of materiel coming down the Ho Chi Minh Trail was being funneled into the three northernmost provinces of South Vietnam, indicating forward stockpiling in preparation for offensive action.

[6]: 15 On 8 December 1970, in response to a request from the Joint Chiefs of Staff, a highly secret meeting was held at the Military Assistance Command, Vietnam's (MACV) Saigon headquarters to discuss the possibility of an ARVN cross-border attack into southeastern Laos.

[22] According to General Creighton W. Abrams, the American commander in South Vietnam, the main impetus for the offensive came from Colonel Alexander M. Haig, an aide to National Security Advisor Dr. Henry Kissinger.

[23]: 230–1  The group's findings were then sent on to the Joint Chiefs in Washington, D.C. By mid-December, President Richard M. Nixon had also become intrigued by possible offensive actions in Laos and had begun efforts to convince both Abrams and the members of his cabinet of the efficacy of a cross-border attack.

When Lãm was finally briefed by MACV and the South Vietnamese Joint General Staff in Saigon, his chief of operations was forbidden to attend the meeting, even though he had helped to write the very plan under discussion.

At the combat base, poor weather, obstacles, land mines and unexploded ordnance pushed the rehabilitation of the airstrip (estimated by U.S. engineers at four days) a week behind schedule.

PAVN resistance was almost nonexistent and American casualties were light; with no previous allied presence around Khe Sanh, the North Vietnamese had seen no need to maintain large forces in the area.

[28]: 29 In order to preserve the security of the upcoming South Vietnamese operation, Abrams had imposed a rare press embargo on the reporting of troop movements, but it was to no avail.

As early as 11 December he had reported to Admiral McCain that: strong infantry, armor, and artillery formations were in southern Laos...formidable air defenses were deployed...the mountainous, jungle-covered terrain was an added liability.

[23]: 235–6 A prescient CIA study released in December 1970 echoed Abrams' concerns and was supported by a 21 January memorandum which "was remarkably accurate with respect to the nature, pattern, and all-out intensity of [PAVN] reactions.

[28]: 120  After a massive preliminary artillery bombardment and 11 B-52 Stratofortress missions, the incursion began on 8 February, when a 4,000-man ARVN armor/infantry task force consisting of the 1st Armored Brigade and the 1st and 8th Airborne Battalions, advanced west unopposed along Route 9.

At 16:55 U.S. helicopter gunships attacked a suspected PAVN target 2 km east of the planned FSB 31 (16°42′54″N 106°25′34″E / 16.715°N 106.426°E / 16.715; 106.426), causing numerous secondary explosions and starting a huge fire which lasted until the following morning.

The helicopter units then became the essential mode of logistical support, a role that was made increasingly more dangerous due to low cloud cover and incessant anti-aircraft fire.

At 12:30 on 10 February troops of the 3rd Airborne Battalion operating 1 km east of FSB 31 were engaged by PAVN, they suffered light casualties, but captured six Molotova trucks loaded with ammunition.

That afternoon the 1/1 Battalion engaged a PAVN unit 3 km south-southwest of LZ Don killing 28 and capturing a storage area containing seven RPDs and large quantities of food.

[5]: 71–2  While the plan called for a quick ground thrust to secure the main objective of Tchepone, the South Vietnamese forces had stalled at A Luoi while awaiting orders to proceed from General Lãm.

At a press conference, Laird claimed that the halt at A Luoi was simply a "pause" that was giving ARVN commanders a chance to "watch and assess enemy movements...The operation is going according to plan.

[5]: 75  On the morning of 18 February the 1st Airborne Battalion conducting a B-52 bomb damage assessment 2 km north of LZ Bravo found an abandoned command post of the PAVN 308th Division.

Thiệu, oblivious to the previous nights attacks, and who was visiting I Corps headquarters at the time, advised Lãm to postpone the advance on Tchepone and to shift the focus of the operation toward the southwest.

[5]: 92 During the night of 3 March the 17th Armored Squadron and 8th Airborne Battalion engaged a battalion-sized PAVN force 5 km north of A Luoi killing 383 and capturing two together with 71 individual and 28 crew-served weapons.

Haig, Nixon's personal military adviser, visited Sutherland in the field and noted Washington's agreement on this point as American fire support might not be available in some later battle, but the Vietnamese were hesitant.

[5]: 100 Their goal in Laos seemingly achieved, Thiệu and Lãm ordered a withdrawal of ARVN forces beginning on 9 March that was to continue through the rest of the month, destroying Base Area 604 and any supplies discovered in their path.

Anti-aircraft fire was increased to halt or slow helicopter resupply or evacuation efforts, the undermanned firebases were attacked and ARVN ground forces had to run a gauntlet of ambushes along Route 9.

One of Kissinger's staff experts, Commander Jonathan Howe, did an extensive survey of all the messages, telephone conversations, and memorandums on the subject that had passed between the White House and the various agencies responsible for the operation.

According to Nixon's chief of staff, H. R. Haldeman, both decided they had been misled by Abrams in the original evaluation of what the operation might accomplish and that they should have followed Westmoreland's advice to cut off the Ho Chi Minh Trail to the south rather than drive toward Tchepone.

[42]: 699 During Lam Son 719, the U.S. planners had believed that any North Vietnamese forces that opposed the incursion would be caught in the open and decimated by the application of American aerial might, either in the form of tactical airstrikes or airmobility, which would provide ARVN troops with superior battlefield maneuvering capability.

Where the Nixon administration had sought to depict the operation as a strictly limited attempt to buy time for Vietnamization, many reporters had come to believe just the opposite, that the president intended to expand the war.

Reporters nevertheless learned some details by interviewing survivors, returning helicopter pilots and the American officers stationed at the border who kept in close touch by radio with the units in the field.

[35]: 447–8  However, despite these efforts by 24 February media coverage turned increasingly pessimistic with reports of the attack on FSB 31 and its subsequent loss raising doubts about the ability of the South Vietnamese to mount such an operation and what its objectives were.