Vietnam 1965: The Evolution and End of the Enclave Strategy

The United States began its involvement in the ground war in South Vietnam with an enclave strategy. That strategy had a short life. It started with the landing of the Marines at Danang in early March and ended less than four months later.[1]

U.S. Ambassador to South Vietnam Maxwell Taylor was an early critic of the enclave strategy. He worried that the deployment of U.S. troops to South Vietnam to hold one or more coastal enclaves would gradually lead the United States into a full-scale war in the interior of South Vietnam. Taylor, who was by no means a dove on Vietnam policy, expressed his concerns to President Johnson as early as January 6, 1965, a full two months before the Marines went ashore at Danang. He wrote, “[The establishment of enclaves] commits U.S. and free world to indefinite direct confrontation with Asiatic Communists…provides a pretext for Communist propaganda charges of U.S. colonialism… [and] It may also be difficult to confine the force to such an enclave in the face of guerrilla attacks which would require ever extending defensive actions beyond perimeter defense.”[2]

Taylor, who had decades of experience as an officer in the U.S. Army, believed that mission creep would propel American combat troops further and further inland. He knew U.S. ground units, once on South Vietnamese soil, would have difficulty remaining inside their enclaves. Gung-ho commanders would seek to destroy the Vietcong threatening their positions. As a result, it would only be a matter of time before U.S. troops were chasing the Vietcong across the South Vietnamese countryside.

But once President Johnson decided to dispatch the Marines to Danang in March 1965, Taylor went along with the decision. For Taylor, the question now became what to do with the troops stationed in South Vietnam. The ambassador thought U.S. troops could best be employed to assist the South Vietnamese Army (ARVN), especially in fighting the Communist main forces. He concluded that strict U.S. adherence to an enclave strategy would not noticeably affect the military balance in South Vietnam – a balance increasingly tipping toward the Vietcong. If U.S. units stayed in their enclaves, the Vietcong would gain greater control over the people and resources of rural South Vietnam, eventually dooming the government in Saigon to complete irrelevance. The former four-star general also assumed that U.S. troops, restricted to enclaves in densely-populated areas, would upset the South Vietnamese, engendering widespread hostility to the U.S. presence.[3] Taylor noted, “There were the obvious risks of deeper military involvement following an initial commitment [to the enclaves] and of adverse psychological reaction of the Vietnamese people to the reappearance of armed white men in their midst in apparent replacement of the hated French.”[4]

Instead of keeping U.S. troops on the edge of the South China Sea, Taylor recommended in March 1965 that U.S. units use the enclaves as jumping-off points into the Central Highlands. He wanted a yet-to-be-determined number of U.S. combat units around Pleiku, the town he considered the geographical center of the entire highlands region. The Pleiku area’s climate, terrain, and low population density would allow U.S. forces to most-effectively employ their mobility and firepower against the Vietcong and North Vietnamese without inflicting excessive casualties on the civilian population. However, Taylor cautioned that U.S. forces deployed to the highlands might be cut off from the coastal enclaves by Vietcong operations, resulting in what he called a “kind of Dien Bien Phu.”[5]

Taylor’s March recommendation, which amounted to a combined enclave-highland positioning of U.S. troops, did not result in any change in U.S. policy. Johnson remained hesitant to send American troops into the interior of South Vietnam, especially as far as Pleiku, fearing that the Vietcong and North Vietnamese, under the leadership of the legendary North Vietnamese General Vo Nguyen Giap, might succeed in pulling off another Dien Bien Phu. So, for the time being, the Marines stayed down on the coast.

Senator Mike Mansfield believed U.S. forces should remain in their coastal enclaves. He thought Johnson would be making a grave mistake if he ordered American troops out of the enclaves then located at Saigon, Danang, Bien Hoa, and Phu Bai and into South Vietnam’s paddy lands. According to Mansfield, U.S. forces had no experience fighting in a tropical environment like the one in South Vietnam, nor did U.S. troops know how to fight as counter-insurgents. Mansfield believed that if U.S. troops ventured into rural South Vietnam, the South Vietnamese peasantry would not lend them any support, making their job of finding and killing the guerrillas nearly impossible. Absent peasant support, the U.S. military effort would stall. And without the military intelligence so necessary to finding, fixing, and destroying the Vietcong, the U.S. expeditionary force would become dangerous and dumb as it bounded blindly through the countryside. Mansfield advised Johnson to hold two or three major enclaves. All U.S. personnel then in South Vietnam, as well as America’s South Vietnamese allies, should be drawn into these American-held enclaves. Once the U.S. had consolidated its position within the enclaves, it could negotiate a compromise political settlement with Hanoi over the future makeup of the government of South Vietnam. Mansfield envisioned the enclaves as bargaining chips, offered to the Communists in exchange for political concessions, such as a role for America’s South Vietnamese allies in a coalition government in Saigon.

Like Taylor, Mansfield feared that General Giap would try and lure U.S. units onto a big base in the Vietnamese hinterland so that he could stage a second Dien Bien Phu. The Montana senator felt strongly that U.S. troops in the Central Highlands faced the very real prospect of entrapment and destruction by the Communists. In a March 24, 1965, memo to Johnson, Mansfield wrote, “From the point of view of our diplomatic position, two or three accessible and more defensible bases will be of greater value than numerous installations in the interior which can become, one by one, the targets of massed Vietcong attacks….”[6]

Mansfield’s recommendation to Johnson underscored a hard truth about the situation on the ground in South Vietnam. In late March 1965, the Vietcong dominated or contested almost all of rural South Vietnam. By one estimate, the Vietcong controlled over ninety percent of South Vietnam’s territory. The Allies held the towns and cities, the Vietcong ruled the hamlets and villages. Mansfield saw South Vietnam as a lost cause; and he firmly believed Johnson would be wise not to try and salvage it. The U.S. should hold a few major enclaves, negotiate a political settlement that gave America’s South Vietnamese allies a say in the future of the southern region, and get the hell out.

Neither President Johnson, Secretary of State Dean Rusk, Secretary of Defense Robert McNamara, nor National Security Adviser McGeorge Bundy accepted Mansfield’s interpretation of the situation prevailing in South Vietnam, particularly the senator’s insistence that the South Vietnamese would not rally to the Americans in the event U.S. forces moved inland to wrest control of the countryside from the Vietcong. Bundy, who wrote Mansfield to express the administration’s position on the issue of South Vietnamese popular opinion, admitted that it was difficult to gauge the attitudes of the South Vietnamese peasantry toward the U.S. presence. Nevertheless, he didn’t think the mass of South Vietnamese peasants would sit on the sidelines if the U.S. went into rural South Vietnam with a large expeditionary force. Rather, Bundy believed that the majority of South Vietnamese (both rural and urban) wanted to be free of Communist influence. Consequently, they would flock to the American banner as soon as the United States made it clear that it had every intention of fighting and defeating the Vietcong. What facts, if any, Bundy relied on to reach this conclusion remains unknown.

On April 1, 1965, President Johnson moved the U.S. one-step closer to a war in the interior of South Vietnam. On that day, he gave the Marines based in the Danang-Phu Bai area authority to engage in limited counter-insurgency operations in the areas surrounding their enclaves.[7] The administration insisted the Marines were still on the defensive and that these counter-insurgency operations were to protect American base areas from Vietcong units known to be operating nearby. This explanation was true. Active patrolling outside the wire at Danang and Phu Bai did enhance security at both bases. Marine patrols kept Vietcong sappers and mortar crews off-balance and away from the bases. But the unstated reason for the counter-insurgency operations was so the Marines could experiment with tactics.

The Pentagon, MACV, and the White House wanted to see how well the Marines did as counter-insurgents in the strange and difficult South Vietnamese environment. Would the Marines find the Vietcong? How well would they operate in the tropics? Would the peasantry resent the American Marines walking through their hamlets? These were some of the questions the administration wanted answered by the Marines. In authorizing the first, limited, counter-insurgency operations, the administration revealed a willingness to abandon the enclave strategy, step into the South Vietnamese countryside, and fight a counter-insurgency war.

Ambassador Taylor responded to Johnson’s decision on Marine counter-insurgency operations by informing Washington that he doubted the Marines would succeed. He noted, “The territorial clear-and-hold mission could have a significant effect in assisting the campaign against the Viet Cong – if successfully implemented. However, it runs into all of the long standing objections to the use of U.S. forces in anti-guerrilla operations in SE Asia.”[8] The ambassador listed several reasons why he thought it ill-advised to adopt a counter-insurgency strategy: U.S. units would suffer high casualties trying to root out local guerrillas in unfamiliar terrain; GIs would have great difficulty distinguishing friend from foe in the countryside’s villages and hamlets, with the likely result that sizable numbers of civilians would die from U.S. firepower; and American forces would not gather the intelligence so crucial to a successful counter-insurgency strategy because they lacked Vietnamese language skills. Taylor warned that American foot patrols, lacking intelligence and patrolling a potentially hostile countryside, would not only not find the enemy, they would be subjected to continual ambush. In his seasoned opinion “…we would have to assume that the newly arrived U.S. forces would have even greater difficulties in finding and fixing the enemy and in protecting themselves against surprise.”[9]

Taylor did not want GIs fighting as counter-insurgents. Instead, he thought they should be used as a mobile reserve. As a mobile reserve, U.S. troops would stay within their enclaves, far from the xenophobic South Vietnamese people, venturing out only after ARVN troops, with their language proficiency and knowledge of local conditions, found and fixed Communist main forces. Taylor judged the helicopter crucial to the success of the mobile reserve concept because of its ability to rapidly carry U.S. troops from their enclaves to any battle site in South Vietnam. In addition, when deployed as a mobile reserve, conventional U.S. units would confront conventional Vietcong and North Vietnamese units, the very type of Soviet-bloc units U.S. troops had been trained and equipped to fight. Thus, U.S. forces would be able to bring to bear their full complement of weapons and equipment, something American counter-insurgents could not do. According to Taylor, the mobile reserve concept played on U.S. strengths, while counter-insurgency operations took away those advantages and invited U.S. defeat.[10] Taylor considered it foolish to place U.S. troops in a counter-insurgency role, since doing so was tantamount to throwing away the U.S.’s tremendous superiority in firepower and mobility.

Nothing was done on Taylor’s mobile reserve proposal. Securing the enclaves continued to be the focus of U.S. operations in April and May 1965. The president and his advisers still wanted to see how the Marines did as counter-insurgents before deciding on a future strategy for the growing U.S. expeditionary force. Johnson also wanted to see how the South Vietnamese units, freed from base defense by the recent U.S. deployments, would do against the Vietcong.

But the Vietcong did not provide the Americans with a chance to learn from the early Marine counter-insurgency operations. Communist units stood down in April and May, keeping the Americans guessing as to the effectiveness of their counter-insurgency operations.

As Johnson contemplated further troop increases, officials at the CIA and State Department warned the president that a massive U.S. bootprint in South Vietnam would not win the war and might lead to a military disaster. Not long after Johnson authorized the Marines to conduct limited counter-insurgency operations, Director of Central Intelligence John McCone, a holdover from the Kennedy administration, advised Johnson that the CIA doubted the efficacy of fighting a major ground war in South Vietnam.

McCone told Johnson that U.S. ground operations, regardless of their scale and intensity, would not in and of themselves break Hanoi’s will to resist. The CIA had concluded that American combat troops could not kill enough enemy troops, or destroy enough enemy war material, to force the Communists out of the war. According to McCone, the only way to end the war in the South on terms favorable to the United States was to put extreme military pressure on North Vietnam. That pressure should be in the form of a massive, unrelenting, bombing campaign over the North. U.S. aircraft should exact a steep price from the North for its participation in the war in the South. Only after the North had felt real pain, and the threatened loss of all of its economic and military capabilities, would Ho Chi Minh and his fellow revolutionaries agree to U.S. terms. If the U.S. limited the destructive effects of air power over the North, which McCone felt was happening with the ongoing Rolling Thunder campaign, the ground war in the South could go on indefinitely, since ground operations in the South, and a sheepish air campaign over the North, would not inflict enough suffering on the North. McCone stated, “…what we are doing is starting on a track which involves ground force operations, which in all probability will have limited effectiveness against guerrillas…we can expect requirements for an ever-increasing commitment of U.S. personnel without materially improving the chances of victory.”[11]

McCone’s advice was not what the president wanted to hear. In the spring of 1965, Johnson hoped that some sort of U.S. pressure on the Communists on the ground in the South (if only through the holding of enclaves or through limited counter-insurgency operations), combined with the Rolling Thunder air campaign over the North, would be enough to convince Hanoi and the Vietcong to quit the struggle. The president understood that the Rolling Thunder campaign and limited ground operations in South Vietnam might not work; but he was also convinced that an air campaign against the North on the scale suggested by McCone would probably lead to Chinese, and possibly Soviet, intervention in the war. McCone thought anything less than a shock and awe air campaign against the North would lead to a stalemate on the ground in the South. McCone’s prognosis for the U.S. on the ground in South Vietnam did not win him any allies in the White House. Feeling marginalized and unappreciated by Johnson and McGeorge Bundy, McCone resigned as Director of Central Intelligence only days after the submission of his memorandum.[12]

On April 22, 1965, McNamara recommended to the president that he increase the U.S. troop level in South Vietnam from an authorized strength of approximately 28,000 to 82,000. The larger force level would include thirteen maneuver battalions, or about 13,000 combat troops. This force was considered necessary to secure the coastal enclaves, as well as the big American airbase at Bien Hoa. The troop augmentation would not give the U.S. an offensive military capability; thus, it reflected the administration’s continued adherence to an enclave strategy. The president approved the troop reinforcement request.[13]

With U.S. units streaming into South Vietnam to hold the enclaves, and with the Marines slowly and ineffectually conducting counter-insurgency operations on the environs of Danang-Phu Bai, the administration tried to conceal the build-up and the tentative moves toward a ground war from the American public. The administration purposely spaced the troop deployments over months to avoid the public perception of a rush to war. Secretary of State Rusk instructed the embassy staff in Saigon, “…deployments, other than Marines, will be spaced over period of time with publicity re[gard] all deployments kept at lowest key possible.”[14] The administration repeatedly informed domestic and international media outlets that the deployments to South Vietnam were necessary to protect U.S. personnel already in the South. Johnson was determined to deceive the U.S. public about the U.S. buildup and the likelihood it might lead to a major ground war.

With U.S. troops pouring into South Vietnam, Clark Clifford, a long-time Washington insider and adviser to Democratic presidents, recognized that the administration, although still holding the enclaves, was steadily sliding toward direct participation in the ground war. The continued troop buildup, plus Marine operations near Danang, were creating their own momentum, pushing the U.S. ever closer to major ground combat with the Vietcong. On May 17, 1965, Clifford cautioned the president, urging him to keep U.S. troops confined to the coastal enclaves. He stated, “I believe our ground forces in South Vietnam should be kept to a minimum, consistent with the protection of our installations and property in that country…This could be a quagmire. It could turn into an open-ended commitment on our part that would take more and more ground troops, without a realistic hope for ultimate victory. I do not think the situation is comparable to Korea. The political posture of the parties involved, and the physical conditions, including terrain are entirely different.”[15] It is not known whether Clifford’s advice influenced the president. Nevertheless, Johnson continued to adhere to an enclave strategy throughout May and well into June.

In mid-May, the Vietcong began an offensive against the Saigon government and its military forces. Vietcong main forces first struck at the ARVN in the Mekong Delta. Then, in late May, Vietcong battalions, some with embedded North Vietnamese regulars, attacked ARVN units along the coastal plain and across the Central Highlands. During these battles, the ARVN, already suffering low morale, high desertion rates, and dismal leadership, either broke and ran or sustained prohibitive casualties. South Vietnamese officials notified the American embassy in Saigon that unless U.S. units began to actively engage the Communist main forces, the ARVN and GVN would not survive the year; South Vietnam would crumble around the American enclaves.

As the monsoon offensive intensified, American military analysts determined that if the ARVN and GVN collapsed, and the U.S. still held a few enclaves, it would not be long before the Vietcong, swollen with new recruits from the countryside and North Vietnamese regulars entering South Vietnam unopposed over the Ho Chi Minh Trail, began shelling the enclaves and infiltrating sappers and agitators behind U.S. lines to undermine American and South Vietnamese authority. Surrounded by a Vietcong-dominated rural population numbering over ten million, and under unrelenting military and political pressure, the U.S. would be forced out of South Vietnam. A U.S. retreat from South Vietnam under such conditions would harm America’s global standing, convincing many in the Communist Bloc that America was indeed a paper tiger – a claim long made by China’s Mao Zedong. Furthermore, the defeat of the U.S. superpower would confirm that wars of national liberation represented an effective means of subverting America’s allies in the developing world. A humiliating retreat from South Vietnam would also personally affect President Johnson, likely ending any chance of his re-election in 1968.

In June 1965, with the ARVN falling back in the face of the Vietcong’s offensive, it became clear to President Johnson that the continued confinement of U.S. units to their enclaves was tantamount to accepting defeat in South Vietnam.

General Philip Davidson, who later served as the MACV intelligence chief, summarized the thinking of U.S. military commanders in Washington and Saigon as the ARVN began to unravel. “The American generals foresaw an even grimmer picture of what the enclave concept would bring. ARVN would not be able to stand up to the Viet Cong in the countryside. Steadily, they would be defeated and driven into the United States enclaves or destroyed and scattered. In time, the United States troops would be surrounded in static defensive positions, subject to artillery fire and to massed attacks by Giap’s NVA Main Forces.”[16]

General William C. Westmoreland explained his reasons for opposing the enclave strategy. “I disagreed with the enclave strategy. As my staff put it at the time, it represented “an inglorious static use of U.S. forces in overpopulated areas with little chance of direct or immediate impact on the outcome of events”…[it] would have no effect on the critical situation in the Central Highlands…it would position American troops in what would be in effect a series of unconnected beachheads, their backs to the sea, essentially in a defensive position. That would leave the decision of when and where to strike to the enemy, [and] invite defeat of each in turn….”[17] Defense Secretary Robert S. McNamara sided with Westmoreland, he too believed that U.S. units, restricted to the enclaves, would be unable to employ their full complement of weapons without visiting extensive destruction upon South Vietnam’s urban areas.[18] The Defense Secretary concluded that keeping U.S. troops inside enclaves doomed South Vietnam to defeat.

Those familiar with South Vietnam’s geography also understood that with an enclave strategy, the Vietcong possessed an important, time-tested military advantage. They would control the high ground. Towering, tree-covered hills reared up immediately west of the Allied enclaves at Nha Trang, Qui Nhon, Danang, and Phu Bai, while the foothills of the Annamese Cordillera stood mere miles from Quang Ngai City and Chu Lai. If the Americans forfeited the high ground to the Vietcong, guerrilla forward observers would be able to direct mortar and artillery fire down on the exposed U.S. positions. Additionally, if the Central Highlands went over to the Vietcong, which would likely happen if U.S. troops stayed down on the coast, the Communists could rapidly move their forces out of that region and against any one of the enclaves. Westmoreland was correct in arguing that the Communists would likely destroy the enclaves one at a time. Giap’s armies had done the same to French enclaves during the First Indochina War.

There was another reason the administration, MACV, and the Joint Chiefs of Staff pondered the abandonment of the enclave strategy. Back in March 1964, President Johnson signed National Security Action Memorandum (NSAM) 288. The memorandum laid out America’s primary strategic objective in South Vietnam. It stated that the U.S. was in South Vietnam to preserve a stable, non-Communist government. What was obvious to the president and his military chiefs was that an enclave strategy would not achieve that overarching goal. If U.S. troops stayed inside the enclaves, the Vietcong would consolidate its hold over rural South Vietnam. And a non-Communist government could not survive in Saigon without control over the majority of the 11.5 million people residing in the countryside, or without the output generated by the agricultural sector, the largest segment of the South Vietnamese economy. Only by moving out of the enclaves and into the countryside and re-occupying South Vietnam’s hamlets and villages, could the U.S. ever hope to achieve the objective set out in NSAM-288. So, in late June 1965, President Johnson abandoned the enclave strategy and embarked on a ground war in the interior of the Asian landmass.


[1] Phillip B. Davidson, Vietnam at War: The History, 1946-197, 1988, Reprint, (New York: Oxford University Press, 1991), 347.

[2] Foreign Relations of the United States (FRUS), 1964-1968, Volume II, Vietnam, January-June, 1965, “Document 13, Telegram From the Embassy in Vietnam to the Department of State, January 6, 1965,” (Washington: GPO, 1996), 27.

[3] FRUS, Volume II, Vietnam, January-June, 1965, “Document 204, Telegram From the Embassy in Vietnam to the Department of State, March 18, 1965,” 456.

[4] Maxwell D. Taylor, Swords and Plowshares: A Memoir, 1972, Reprint, (New York: Da Capo Press, 1990), 239.

[5] Ibid. 457.

[6] FRUS, Volume II, Vietnam, January-June, 1965, “Document 215, Letter From Senator Mike Mansfield to President Johnson, March 24, 1965,” 479.

[7] FRUS, Volume II, Vietnam, January-June, 1965, “Document 230, Memorandum From Director of Central Intelligence McCone to the Deputy Director of Central Intelligence (Carter), April 1, 1965,” 513; FRUS, Volume II, Vietnam, January-June, 1965, “Document 239, Telegram From the Department of State to the Embassy in Vietnam, April 3, 1965,” 532.

[8] FRUS, Volume II, Vietnam, January-June, 1965, “Document 218, Telegram From the Embassy in Vietnam to the Department of State, March 27, 1965,” 488.

[9] Ibid. 488-489.

[10] Ibid. 489.

[11] FRUS, Volume II, Vietnam, January-June, 1965, “Document 234, Letter From Director of Central Intelligence McCone to President Johnson, Attachment, Memorandum From Director of Central Intelligence McCone to Secretary of State Rusk, April 2, 1965,” 523.

[12] New York Times, “John A. McCone, Head of C.I.A. in Cuban Missile Crisis Dies at 89,” Glenn Fowler, February 16, 1991.

[13] FRUS, Volume II, Vietnam, January-June, 1965, “Document 271, Telegram From the Department of State to the Embassy in Vietnam, April 22, 1965,” 602.

[14] FRUS, Volume II, Vietnam, January-June, 1965, “Document 239, Telegram From the Department of State to the Embassy in Vietnam, April 3, 1965,” 532.

[15] FRUS, Volume II, Vietnam, January-June, 1965, “Document 307, Letter From Clark M. Clifford to President Johnson, May 17, 1965,” 672.

[16] Davidson, Vietnam at War, 346.

[17] William C. Westmoreland, A Soldier Reports, (Garden City, New York: Doubleday & Company, Inc., 1976), 130.

[18] Robert S. McNamara, James G. Blight and Robert K. Brigham, Argument Without End: In Search of Answers to the Vietnam Tragedy, (New York: PublicAffairs, 1999), 418.

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