In January 1966, General William C. Westmoreland ordered the 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 movement 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 decided to keep the Marines at Khe Sanh. He made this decision because he believed the base and its troops fulfilled two important military roles.
First, Westmoreland believed the Marines had to occupy the base in the event President Johnson authorized a cross-border invasion of Laos to cut the Ho Chi Minh Trail. Without Khe Sanh, and its airstrip, an invasion along Route 9 into Laos would be far more difficult, especially from the perspective of logistics. Plus, the Marines at the base could serve to protect the right flank of any future invasion force.
Secondly, Westmoreland thought the base and its Marine contingent threw the enemy in Laos off-balance. Khe Sanh’s Marine contingent 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 their rear areas. Thus, the Communists, Westmoreland concluded, would have to allocate a certain number of troops to the defense 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 would decrease the number of Communist soldiers available for combat in South Vietnam, which would result in fewer U.S. casualties.
Although Westmoreland’s justifications for deploying the Marines to Khe Sanh made tactical sense, the base may have had little influence on Giap’s military plans. The Communist general probably understood that he would have plenty of advance warning of any major U.S. thrust into Laos because the logistical preparations for such an invasion would be readily apparent 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 imminent.
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 also 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 GIs in the defense 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 defense 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 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, Westmoreland’s long-time mentor, former U.S. Ambassador to South Vietnam, Maxwell Taylor, questioned the necessity of holding Khe Sanh. “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 favor 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. Cushman 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. The Marine general did not consider the American border bases necessary to the defense 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 holding the 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 Marines 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. Instead of holding static positions, 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 regularly 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 defense played on U.S. strengths in mobility, air support and communications, while a stationary U.S. defense played on the enemy’s strengths in camouflage, tunneling, 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.