Its objectives were the use of recently captured Salavan as a jumpoff point for occupying Tha Theng and Ban Phong.

However, they lost both Salavan and Paksong to the North Vietnamese; they also failed to find the Communist transshipment point whose conquest would have interdicted the Trail.

In the wake of this failure, CIA backed Laotian guerrillas and Royal Lao Government military irregulars made further attempts at severing the logistical lines of communication.

[4] In mid-May 1971, Operation Phoutah failed to secure the forward airfield at Moung Phalane as a starting point for Royalist attacks against the Trail.

[6] From 28 July through 31 October 1971, Operation Sayasila managed to wrest control of Route 23 and the towns of Salavan and Paksong and their associated airstrips from the (PAVN), but failed to conquer the entire Bolaven Plateau.

[8] Operation Thao La was planned to take advantage of improved flying weather during the nascent dry season in Laos.

[12] On 16 November, just prior to Thao La's scheduled start, a purported four battalion force of PAVN were reported by Royalist guerrillas, 19 kilometers northwest of Salavan.

On 21 November, USAF F-4 Phantom IIs struck the HLZ, and the 1,150 Royalist guerrillas of the Groupement Mobile 33 (GM 33) regiment was lifted in unopposed from Salavan.

After capturing the position, the fourth Royalist battalion of GM 41 established a fire base with a 75mm pack howitzer, three 75mm recoilless rifles, and three 81mm mortars.

[9][16] On 28 November, GM 33 began clearing Route 16 and its surrounding valley as it handed westward to link up with the Royalist troops in Tha Theng.

Stretching into battalion line, the irregular regiment swept for PAVN rice caches and supply depots to deprive the Communists of materiel.

As a counter, the USAF honored an emergency request and dropped aerial denial ordnance along two projected approach lanes to Tha Theng.

The USAF also consented to extending the supply of 24 sorties of daily tactical air power for Thao La through 27 December 1971.

By the end of the first week in December, Raven FACs noticed freshly built PAVN bunkers within 50 meters of Paksong's defenses.

One of the tanks penetrated the Tha Theng perimeter, locked one tread, and spun on the other while firing in all directions, dispersing two of the Royalist guerrilla battalions.

[22] Presented with the dilemma of which objective was most valuable to their cause, the RLG opted on attempting to retake Salavan while holding Tha Theng.

Leaving a small partisan garrison at Tha Theng, the RLG elected to move its four irregular battalions north for a surprise counterattack on Salavan.

A USAF mission dropped both defensive area denial munitions and land mines under direction of Raven FACs.

The Tha Theng irregulars directed tactical air strikes on the PAVN on 22 and 23 December despite poor flying weather; they followed up with a ground assault.

Even as a purported 1,000 PAVN troops bombarded forward positions at Paksong with mortar fire, making them difficult to reinforce and resupply, they also angled to cut Route 23 to entrap the Royalists.

During the next two days, a number of PAVN heavy machine guns moved in on Paksong, complicating Royalist-backed aerial traffic.

[27] Operation Thao La gained its two objectives of Tha Theng and Ban Phong by its official end on 16 December.

It also failed to break the PAVN's grip on the eastern Bolavan Plateau where it overwatched the Ho Chi Minh Trail.