In January 1966, General William C. Westmoreland ordered the U.S. Marines to the Khe Sanh Combat Base in western Quang Tri Province. Westmoreland wanted the Marines to curtail North Vietnamese infiltration into South Vietnam along the system of trails known collectively as the Ho Chi Minh Trail. But like the Green Berets stationed at the base before them, the Marines failed to halt, or even slow, the flow of Communist soldiers and supplies pouring into South Vietnam. The same weather and tough terrain that had made it impossible for the Green Berets to stop North Vietnamese infiltration also thwarted the Marines.
In the first year of the Marine deployment to Khe Sanh, the North Vietnamese infiltrated an estimated 62,000 men into South Vietnam. In 1967, another 101,000 North Vietnamese came down the Ho Chi Minh Trail and entered South Vietnam.
Despite the inability of the Marines to do anything about North Vietnamese infiltration, Westmoreland kept the Marines at Khe Sanh. The general believed the base and its troops fulfilled important military objectives. Most importantly, Westmoreland wanted the base occupied in the event President Johnson authorized a cross-border invasion of Laos to cut the Ho Chi Minh Trail. If Johnson gave the order to go into Laos, the United States would need Khe Sanh as a staging base.
Westmoreland also believed the base and its Marine contingent threw the enemy in Laos off-balance. Khe Sanh kept North Vietnamese General Vo Nguyen Giap and his subordinate commanders guessing as to U.S. intentions in the area. With so many Marines in western Quang Tri Province, Communist commanders could not be entirely sure of the security of the Ho Chi Minh Trail or of their rear areas. Thus, the Communists, Westmoreland concluded, would have to allocate a certain number of troops to the defence of the trail whenever they made plans for major operations in South Vietnam. Any deployment of North Vietnamese troops to defend the trail against an American cross-border invasion decreased the number of Communist soldiers available for combat in South Vietnam, which would then translate into fewer U.S. casualties.
Although Westmoreland’s justifications for deploying the Marines to Khe Sanh made tactical sense, the base had little effect on Giap’s military plans. The Communist general understood that he would have plenty of advance warning of any U.S. thrust into Laos from Khe Sanh because the huge logistical preparations for such an invasion would be readily discernible at Phu Bai, Ca Lu, Camp Carroll, Cam Lo, and of course Khe Sanh. The North Vietnamese had no need to alter their deployment plans in the Khe Sanh area unless it became clear that a cross-border incursion was in the offing.
In April 1967, the Marines fought to dislodge the North Vietnamese from the hills west and south of the base, which were being utilized as forward observation posts for Communist mortar and artillery gunners. Over the course of twelve days, the Marines and North Vietnamese regulars fought a succession of vicious battles for hills 881 North, 881 South, and 861 – all of which overlooked the base’s airstrip. Aided by repeated airstrikes, the Marines eventually took the high points. An estimated 600 North Vietnamese lost their lives in what became known as the “hill fights.” Over 150 Marines died in the series of savage battles.
The hill fights were significant, not because the hills were taken, but because of how U.S. losses influenced Westmoreland’s later decision to stay and reinforce Khe Sanh. Following the death and wounding of so many G.I.’s in the defence of the base, it became politically difficult for Westmoreland to abandon Khe Sanh at a later date. Although the base was not crucial to the defence of South Vietnam, the Marine deaths made it symbolically important. Khe Sanh had been invested with American blood. To withdraw from the base would have invited public criticism of Westmoreland’s conduct of the war, especially his willingness, during the hill fights, to throw away American lives in assaults against dug-in enemy soldiers on hilltops in the remote Central Highlands. One U.S. official summed up how the hill fights influenced Westmoreland’s later decision-making, “…for psychological and political reasons we wouldn’t want to pull back…what would the newspapers have written if we had given up Khe Sanh afterward.”
In the wake of the hill fights, not everyone on the U.S. general staff in South Vietnam agreed with Westmoreland’s decision to hold on to Khe Sanh. One of those who questioned the necessity of defending Khe Sanh was Westmoreland’s long-time mentor, former U.S. Ambassador to South Vietnam, Maxwell Taylor. “I thought he [Westmoreland] should be told that, in this phase of the conflict, remote terrain along the frontiers of South Vietnam meant nothing in itself insofar as Washington was concerned, that the President and his advisors looked with favour on the avoidance of combat close to the cross-border sanctuaries of the enemy where he had the advantage of short lines of communications, and that they [in the administration] saw no advantage in paying a high price to hold exposed outposts like Khe Sanh.”
General Robert Cushman, who commanded the Marines in I Corps, shared Taylor’s concerns. At the time, he wanted to abandon Khe Sanh and the other static defensive positions along the southern edge of the Demilitarized Zone (DMZ), including Con Thien and Gio Linh. Cushman did not consider the American border bases necessary to the defence of South Vietnam. He also thought the bases sat too close to Communist strongholds in Laos and North Vietnam, which increased their vulnerability to enemy artillery, rockets, and mortar fire.
According to Cushman, the Marines strung out on bases south of the DMZ were nothing more than sitting ducks, waiting to be slaughtered by the Communists’ deadly accurate artillery fire and Russian-made rockets. Cushman felt that the intense bombardment of Con Thien in late September 1967 proved his point. During the Con Thien battle, the North Vietnamese hid their heavy artillery in camouflaged and fortified emplacements in and around the DMZ, firing on Con Thien with near impunity. Cushman considered it insane to subject his troops to such fire. He also disputed the argument made at MACV headquarters in Saigon that the Marines at Con Thien had checked North Vietnamese infiltration across the DMZ. That argument, he thought, was preposterous. The thousands of rounds raining down on Con Thien had driven the Marines underground. Once restricted to their bunkers, the Marines were unable to leave the base to halt enemy infiltration.
Cushman wanted his Marines withdrawn from their forward bases. Doing so would ensure that his troopers were less exposed to Communist artillery fire. He proposed the establishment of a buffer zone of between six and eight miles between the southern DMZ and the Mieu Giang River. Within this zone, the Marines would keep constantly on the move, not erecting any permanent posts. In order to inflict casualties on the mobile American units, the North Vietnamese would have to constantly redeploy their own units and artillery. The frequent redeployment of Communist units would reveal their artillery and troop formations to U.S. aerial spotters, who could then call-in air strikes, artillery fire, naval gunfire, and fast-moving Marine mechanized units to destroy the North Vietnamese out in the open.
Cushman’s plan for a flexible defence played on U.S. strengths in mobility, air support and communications, while a stationary U.S. defence played on the enemy’s strengths in camouflage, tunnelling, and long-range artillery bombardment. Unfortunately for the Marines, Westmoreland rejected Cushman’s proposal. He ordered the Marines to continue to hold the bases along the DMZ, regardless of their exposure to North Vietnam’s long-range artillery, rockets, and mortars. That decision, which Cushman vehemently opposed, ultimately set the stage for the siege of Khe Sanh in 1968.
 Lewis Sorley, ed., Vietnam Chronicles: The Abrams Tapes, 1968-1972, (Lubbock: Texas Tech University Press, 2004), 675.
 New York Times, “Khesanh: Why U.S. is Making a Stand,” Neil Sheehan, February 23, 1968.
 Maxwell D. Taylor, Swords and Plowshares: A Memoir, (New York: W.W. Norton & Company, 1972, Reprint, De Capo Press, Date Unknown), 389.
 John Laurence, The Cat from Hue: A Vietnam War Story, (New York: Touchstone, 2002), 449.
 New York Times, “Khesanh: Why U.S. is Making a Stand,” Neil Sheehan, February 23, 1968; Lewis Sorley, Westmoreland: The General Who Lost Vietnam, (New York: Houghton Mifflin Harcourt, 2011), 169.