Vietnam Climax
Siege of Khe Sanh

Khe Sanh in Wargames

by John Prados

The notion that Khe Sanh represented critical terrain, a platform for operations into Laos, and a key patrol base below the Demilitarized Zone, was never something simply dreamed up by an armchair general. Instead it was a product of close analysis of the lay of the land. That analysis would be reinforced by the results of military map exercises.

And far from some last minute realization just prior to the onset of battle, this understanding of the role and importance of Khe Sanh dated from very early in the Vietnam war. Even as the battle raged, moreover, General Westmoreland turned to his staff for studies of sieges in history to help him anticipate the likely results of the combat raging at Khe Sanh.

Back during the years of the Kennedy administration there were repeated discussions in Washington as senior officials advocated an invasion of southern Laos, called the panhandle, as a means of cutting the Ho Chi Minh Trail. This became a variant on a plan concocted by the Southeast Asia Treaty Organization (SEATO) and designed to save the Mekong River valley of Laos from encroachments by the Pathet Lao.

In March and April 1962 the SEATO plan was rehearsed in a multinational maneuver called TULUNGUN, after colloquial Filipino word for "mutual assistance." The exercise involved actual operations in the Philippines, where a SEATO force landed on the west coast of Mindoro and pushed cross-country, in much the same way a force might move overland from the Vietnamese coast across Route 9 to Khe Sanh and then Tchepone. Because, by international agreement, South Vietnam was a regroupment zone not a country, and was prohibited from participating in SEATO, Vietnamese territory could not be used for activities like this. The exercise nevertheless drew attention to difficulties of overland supply. In Vietnam, Khe Sanh would necessarily have played a key role in any such operation.

Also in early 1962, but in the United States, a large scale maneuver at Fort Berming by the 11th Air Assault Division, the Army's prototype for what became the 1st Cavalry Division (Airmobile), used the scenario of the unit conducting major raids in the Laotian panhandle against the Ho Chi Minh Trail. Although the exercise featured the division basing itself in Thailand, rather than Vietnam, not least due to better security conditions there, it seemed apparent that action would be much less effective unless complemented by thrusts from the Vietnamese side of The Trail. The only feasible launch point for operations out of South Vietnam would be Khe Sanh.

Maneuvers moved from the field to the map table in 1966. At that time, with General William Westmoreland now in command of MACV, there were differences between the theater commander and the Marine leaders of III MAF, over how well defended was Khe Sanh. Westmoreland would be concerned for much of his Vietnam tour regarding the state of the threat to the part of Saigon's territory just below the Demilitarized Zone, and saw III MAF at that time as putting too much of its effort into Pacification issues.

In late summer Westy ordered III MAF to wargame the situation. The Marines found the area to be defensible provided outlying posts like Khe Sanh were evacuated and the main line of resistance was placed in the Annamite foothills, a conclusion Westmoreland rejected.

In September, reviewing the results of this wargame, the MACV commander ordered III MAF leaders to restudy the situation and stated his belief the Marines were underestimating the threat in the northernmost provinces. These pressures from MACV were important in the III NLkF decision to increase Khe Sanlis garrison to a battalion-size force in 1967.

During the fall of 1967, when U.S. intelligence began to receive indications that Hanoi was moving major units down the Ho Chi Minh Trail, Westmoreland ordered MACV intelligence and operations staffs to perform a fresh assessment of the Khe Sanh situation. The staff study did not actually go to a map maneuver, but it did do a sort of scripted simulation, in which officers postulated various possible enemy moves and operations specialists described how they would counter them. The results were presented to General Westmoreland late in November, as he returned from a visit to the United States.

Westy directed that the briefing be repeated for III commanders at Da Nang. When that meeting took place Marine General Robert E. Cushman decided the conclusions made good sense, and that the threat was more likely to center on Khe Sanh than such other lowland bases as Camp Carroll or Con Thien. Cushman determined to reinforce Khe Sanh as Hanoi's troops approached it, thus beginning the stream of fresh units that arrived at the combat base in the final weeks before the siege began.

One more study that bears mention took place during the actual battle. Seeking to short circuit negative attitudes and defeatism in his own command structure' General Westmoreland asked the MACV historian, Colonel Reamer W Argo, to perform an analysis that compared Khe Sanh with Dien Bien Phu, as well as a broader investigation of sieges in history. Colonel Argo went back to 1453 and the siege of Constantinople and identified thirty-nine separate instances for examination. He concluded that in the middle ages fortresses had had a fair record in withstanding sieges, but that the advent of gunpowder had reduced the interval necessary to breach defenses to a period often within the endurance of besieging forces. The forfeiture of initiative by defending forces and the supply problems which developed were crucial drawbacks.

Argo's study discounted reinforcing Khe Sanh as merely upping the ante for the North Vietnamese and advised that "urgent consideration" be given to employing an outside force for offensive action against the siege forces.

General Westmoreland took the floor following the presentation to insist that Khe Sanh was not like other sieges, that the battle would not be lost, and that he would not tolerate any talking or even thinking otherwise. Westy nevertheless went ahead to plan the PEGASUS relief operation and to gather the outside offensive force that Reamer Argo had advocated. And the rest, as people say, is history.

Vietnam Climax Siege of Khe Sanh

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