The Vietnam War was the legacy of France's failure to suppress nationalist forces in Indochina as it struggled to restore its colonial dominion after World War II. Led by Ho Chi Minh, a Communist-dominated revolutionary movement-the Viet Minh-waged a political and military struggle for Vietnamese independence that frustrated the efforts of the French and resulted ultimately in their ouster from the region.

The U.S. Army's first encounters with Ho Chi Minh were brief and sympathetic. During World War II, Ho's anti-Japanese resistance fighters helped to rescue downed American pilots and furnished information on Japanese forces in Indochina. U.S. Army officers stood at Ho's side in August 1945 as he basked in the short-lived satisfaction of declaring Vietnam's independence. Five years later, however, in an international climate tense with ideological and military confrontation between Communist and non-Communist powers, Army advisers of the newly formed U.S. Military Assistance Advisory Group (MAAG), Indochina, were aiding France against the Viet Minh. With combat raging in Korea and mainland China recently fallen to the Communists, the war in Indochina now appeared to Americans as one more pressure point to be contained on a wide arc of Communist expansion in Asia. By underwriting French military efforts in Southeast Asia, the United States enabled France to sustain its economic recovery and to contribute, through the North Atlantic Treaty Organization (NATO), to the collective defense of Western Europe.

Provided with aircraft, artillery, tanks, vehicles, weapons, and other equipment and supplies a small portion of which they distributed to an anti-Communist Vietnamese army they had organized-the French did not fail for want of equipment. Instead, they put American aid at the service of a flawed strategy that sought to defeat the elusive Viet Minh in set-piece battles, but neglected to cultivate the loyalty and support of the Vietnamese people. Too few in number to provide more than a veneer of security in most rural areas, the French were unable to suppress the guerrillas or to prevent the underground Communist shadow government from reappearing whenever French forces left one area to fight elsewhere.

The battle of Dien Bien Phu epitomized the shortcomings of French strategy. Located near the Laotian border in a rugged valley of remote northwestern Vietnam, Dien Bien Phu was not a congenial place to fight. Far inland from coastal supply bases and with roads vulnerable to the Viet Minh, the base depended almost entirely on air support. The French, expecting the Viet Minh to invade Laos, occupied Dien Bien Phu in November 1953 in order to force a battle. Yet they had little to gain from an engagement. Victory at Dien Bien Phu would not have ended the war; even if defeated, the Viet Minh would have retired to their mountain redoubts. And no French victory at Dien Bien Phu would have reduced Communist control over large segments of the population. On the other hand, the French had much to lose, in manpower, equipment, and prestige.

Their position was in a valley, surrounded by high ground that the Viet Minh quickly fortified. While bombarding the besieged garrison with artillery and mortars, the attackers tunneled closer to the French positions. Supply aircraft that successfully ran the gauntlet of intense antiaircraft fire risked destruction on the ground from Viet Minh artillery. Eventually, supplies and ammunition could be delivered to the defenders only by parachute drop. As the situation became critical, France asked the United States to intervene. Believing that the French position was untenable and that even massive American air attacks using small nuclear bombs would be futile, General Matthew B. Ridgway, the Army Chief of Staff, helped to convince President Dwight D. Eisenhower not to aid them. Ridgway also opposed the use of U.S. ground forces, arguing that such an effort would severely strain the Army and possibly lead to a wider war in Asia.

The fall of Dien Bien Phu on 7 May 1954, as peace negotiations were about to start in Geneva, hastened France's disengagement from Indochina. On 20 July, France and the Viet Minh agreed to end hostilities and to divide Vietnam temporarily into two zones at the 17th parallel. In the North, the Viet Minh established a Communist government, with its capital at Hanoi. French forces withdrew to the South, and hundreds of thousands of civilians, most of whom were Roman Catholics, accompanied them. The question of unification was left to be decided by an election scheduled for 1956.

As the Viet Minh consolidated control in the North, Ngo Dinh Diem, a Roman Catholic of mandarin background, sought to assert his authority over the chaotic conditions in the South in hopes of establishing an anti-Communist state. A onetime minister in the French colonial administration, Diem enjoyed a reputation for honesty. He had resigned his office in 1933 and had taken no part in the tumultuous events that swept over Vietnam after the war. Diem returned to Saigon in the summer of 1954 as premier with no political following except his family and a few Americans. His authority was challenged, first by the independent Hoa Hao and Cao Dai religious sects and then by the Binh Xuyen, an organization of gangsters that controlled Saigon's gambling dens and brothels and had strong influence with the police. Rallying an army, Diem defeated the sects and gained their grudging allegiance. Remnants of their forces, however, fled to the jungle to continue their resistance, and some, at a later date, became the nucleus of Communist guerrilla units.

Members of his own army also challenged Diem, where French influence persisted among the highest-ranking officers. But he weathered the threat of an army coup, dispelling American doubts about his ability to survive in the jungle of Vietnamese politics. For the next few years, the United States commitment to defend South Vietnam's independence was synonymous with support for Diem. Americans now provided advice and support to the Army of the Republic of Vietnam (ARVN); at Diem's request, they replaced French advisers throughout his nation's military establishment.

As the American role in South Vietnam was growing, U.S. defense policy was undergoing review. Officials in the Eisenhower administration believed that wars like those in Korea and Vietnam were too costly and ought to be avoided in the future. "Never again" was the rallying cry of those who opposed sending U.S. ground forces to fight a conventional war in Asia. Instead, the Eisenhower administration relied on the threat or use of massive nuclear retaliation to deter or, if necessary, to defeat the armies of the Soviet Union or Communist China. The New Look, as this policy was called, emphasized nuclear air power at the expense of conventional ground forces. If deterrence failed, planners envisioned the next war as a short, violent nuclear conflict of a few days' duration, conducted with forces in being. Ground forces were relegated to a minor role, and mobilization was regarded as an unnecessary luxury. In consequence, the Army's share of the defense budget decreased, the modernization of its forces was delayed, and its strength was reduced by 40 percent-from 1,404,598 in 1954 to 861,964 in 1956.

A strategy dependent on one form of military power, the New Look was sharply criticized by soldiers and academics alike. Unless the United States was willing to risk destruction, critics argued, the threat of massive nuclear retaliation had little credibility. General Ridgway and his successor, General Maxwell D. Taylor, were vocal opponents. Both advocated balanced forces to enable the United States to cope realistically with a variety of military contingencies. The events of the late 1950's appeared to support their demand for flexibility. The United States intervened in Lebanon in 1956 to restore political stability there. Two years later an American military show of force in the Straits of Taiwan helped to dampen tensions between Communist China and the Nationalist Chinese Government on Formosa. Both contingencies underlined the importance of avoiding any fixed concept of war.

Advocates of the flexible response doctrine foresaw a meaningful role for the Army as part of a more credible deterrent and as a means of intervening, when necessary, in limited and small wars. They wished to strengthen both conventional and unconventional forces; to improve strategic and tactical mobility; and to maintain troops and equipment at forward bases, close to likely areas of conflict. They placed a premium on highly responsive command and control, to allow a close meshing of military actions with political goals. The same reformers were deeply interested in the conduct of brushfire wars, especially among the underdeveloped nations. In the so-called third world, competing cold war ideologies and festering nationalistic, religious, and social conflicts interacted with the disruptive forces of modernization to create the preconditions for open hostilities. Southeast Asia was one of several such areas identified by the Army. Here the United States' central concern was the threat of North Vietnamese and perhaps Chinese aggression against South Vietnam and other non-Communist states.

The United States took the lead in forming a regional defense pact, the Southeast Asia Treaty Organization (SEATO), signaling its commitment to contain Communist encroachment in the region. Meanwhile the 342 American advisers of MAAG, Vietnam (which replaced MAAG, Indochina, in 1955), trained and organized Diem's fledgling army to resist an invasion from the North. Three MAAG chiefs-Lt. Gens. John W. O'Daniel, Samuel T. Williams, and Lionel C. McGarr-reorganized South Vietnam's light mobile infantry groups into infantry divisions, compatible in design and mission with U.S. defense plans. The South Vietnamese Army, with a strength of about 150,000, was equipped with standard Army equipment and given the mission of delaying the advance of any invasion force until the arrival of American reinforcements. The residual influence of the army's earlier French training, however, lingered in both leadership and tactics. The South Vietnamese had little or no practical experience in administration and the higher staff functions, from which the French had excluded them.

The MAAG's training and reorganization work was often interrupted by Diem's use of his army to conduct "pacification" campaigns to root out stay-behind Viet Minh cadre. Hence responsibility for most internal security was transferred to poorly trained and ill-equipped paramilitary forces, the Civil Guard and Self-Defense Corps, which numbered about 75,000. For the most part, the Viet Minh in the South avoided armed action and subscribed to a political action program in anticipation of Vietnam-wide elections in 1956, as stipulated by the Geneva Accords. But Diem, supported by the United States, refused to hold elections, claiming that undemocratic conditions in the North precluded a fair contest. (Some observers thought Ho Chi Minh sufficiently popular in the South to defeat Diem.) Buoyed by his own election as President in 1955 and by the adulation of his American supporters, Diem's political strength rose to its apex. While making some political and economic reforms, he pressed hard his attacks on political opponents and former Viet Minh, many of whom were not Communists at all but patriots who had joined the movement to fight for Vietnamese independence.

By 1957 Diem's harsh measures had so weakened the Viet Minh that Communist leaders in the South feared for the movement's survival there. The southerners urged their colleagues in the North to sanction a new armed struggle in South Vietnam. For self-protection, some Viet Minh had fled to secret bases to hide and form small units. Others joined renegade elements of the former sect armies. From bases in the mangrove swamps of the Mekong Delta, in the Plain of Reeds near the Cambodian border, and in the jungle of War Zones C and D northwest of Saigon, the Communists began to rebuild their armed forces, to re-establish an underground political network, and to carry out propaganda, harassment, and terrorist activities. As reforms faltered and Diem became more dictatorial, the ranks of the rebels swelled with the politically disaffected.

The insurgents, now called the Viet Cong, had organized several companies and a few battalions by 1959, the majority in the Delta and the provinces around Saigon. As Viet Cong military strength increased, attacks against the paramilitary forces, and occasionally against the South Vietnamese Army, became more frequent. Many were conducted to obtain equipment, arms, and ammunition, but all were hailed by the guerrillas as evidence of the government's inability to protect its citizens. Political agitation and military activity also quickened in the Central Highlands, where Viet Cong agents recruited among the Montagnard tribes. In 1959, after
assessing conditions in the South, the leaders in Hanoi agreed to resume the armed struggle, giving it equal weight with political efforts to undermine Diem and reunify Vietnam. To attract the growing number of anti-Communists opposed to Diem, as well as to provide a democratic facade for administering the party's policies in areas controlled by the Viet Cong, Hanoi in December 1960 created the National Liberation Front of South Vietnam. The revival of guerrilla warfare in the South found the advisory group, the South Vietnamese Army, and Diem's government ill prepared to wage an effective campaign. In their efforts to train and strengthen Diem's army, U.S. advisers had concentrated on meeting the threat of a conventional North Vietnamese invasion. The ARVN's earlier antiguerrilla campaigns, while seemingly successful, had been carried out against a weak and dormant insurgency. The Civil Guard and Self-Defense Corps, which bore the brunt of the Viet Cong's attacks, were not under the MAAG's purview and proved unable to cope with the audacious Viet Cong. Diem's regime, while stressing military activities, neglected political, social, and economic reforms. American officials disagreed over the seriousness of the guerrilla threat, the priority to be accorded political or military measures, and the need for special counterguerrilla training for the South Vietnamese Army. Only a handful of the MAAG's advisers had personal experience in counterinsurgency warfare.

Yet the U.S. Army was not a stranger to such conflict. Americans had fought insurgents in the Philippines at the turn of the century, conducted a guerrilla campaign in Burma during World War II, helped the Greek and Philippine Governments to subdue Communist insurgencies after the war, and studied the French failure in Indochina and the British success in Malaya. The Army did not, however, have a comprehensive doctrine for dealing with insurgency. For the most part, insurgent warfare was equated with the type of guerrilla or partisan struggles carried out during World War II behind enemy lines in support of conventional operations. This viewpoint reduced antiguerrilla warfare to providing security against enemy partisans operating behind friendly lines.

Almost totally lacking was an appreciation of the political and social dimensions of insurgency and its role in the larger framework of revolutionary war. Insurgency meant above all a contest for political legitimacy and power-a struggle between contending political cultures over the organization of society. Most of the Army advisers and Special Forces who were sent to South Vietnam in the early 1960'S were poorly prepared to wage such a struggle. A victory for counterinsurgency in South Vietnam would require Diem's government not only to outfight the guerrillas, but to compete successfully with their efforts to organize the population in support of the government's cause.

The Viet Cong thrived on their access to and control of the people, who formed the most important part of their support base. The population provided both economic and manpower resources to sustain and expand the insurgency; the people of the villages served the guerrillas as their first line of resistance against government intrusion into their "liberated zones" and bases. By comparison with their political effort, the strictly military aims of the Viet Cong were secondary. The insurgents hoped not to destroy government forces-although they did so when weaker elements could be isolated and defeated-but by limited actions to extend their influence over the population. By mobilizing the population, the Viet Cong compensated for their numerical and material disadvantages. The rule of thumb that ten soldiers were needed to defeat one guerrilla reflected the insurgents" political support rather than their military superiority. For the Saigon government, the task of isolating the Viet Cong from the population was difficult under any circumstances and impossible to achieve by force alone.

Viet Cong military forces varied from hamlet and village guerrillas, who were farmers by day and fighters by night, to full-time professional soldiers. Organized into squads and platoons, part-time guerrillas had several military functions. They gathered intelligence, passing it on to district or provincial authorities; they proselytized, propagandized, recruited, and provided security for local cadres. They reconnoitered the battlefield, served as porters and guides, created diversions, evacuated wounded, and retrieved weapons. Their very presence and watchfulness in a hamlet or village inhibited the population from aiding the government.

By contrast, the local and main force units consisted of full-time soldiers, most often recruited from the area where the unit operated. Forming companies and battalions, local forces were attached to a village, district, or provincial headquarters. Often they formed the protective shield behind which a Communist Party cadre established its political infrastructure and organized new guerrilla elements at the hamlet and village levels. As the link between guerrilla and main force units, local forces served as a reaction force for the former and as a pool of replacements and reinforcements for the latter. Having limited offensive capability, local forces usually attacked poorly defended, isolated outposts or weaker paramilitary forces, often at night and by ambush. Main force units were organized as battalions, regiments, and-as the insurgency matured-divisions. Subordinate to provincial, regional, and higher commands, such units were the strongest, most mobile, and most offensive-minded of the Viet Cong forces; their mission often was to attack and defeat a specific South Vietnamese unit.

Missions were assigned and approved by a political officer who, in most cases, was superior to the unit's military commander. Party policy, military discipline, and unit cohesion were inculcated and reinforced by three-man party cells in every unit. Among the insurgents, war was always the servant of policy.

As the Viet Cong's control over the population increased, their military forces grew in number and size. Squads and platoons became companies, companies formed battalions, and battalions were organized into regiments. This process of creating and enlarging units continued as long as the Viet Cong had a base of support among the population. After 1959, however, infiltrators from the North also became important. Hanoi activated a special military transportation unit to control overland infiltration along the Ho Chi Minh Trail through Laos and Cambodia. Then a special naval unit was set up to conduct sea infiltration. At first, the infiltrators were southern-born Viet Minh soldiers who had regrouped north after the French Indochina War. Each year until 1964, thousands returned south to join or to form Viet Cong units, usually in the areas where they had originated. Such men served as experienced military or political cadres, as technicians, or as rank-and-file combatants wherever local recruitment was difficult.

When the pool of about 80,000 so-called regroupees ran dry, Hanoi began sending native North Vietnamese soldiers as individual replacements and reinforcements. In 1964 the Communists started to introduce entire North Vietnamese Army (NVA) units into the South. Among the infiltrators were senior cadres, who manned the expanding Viet Cong command system- regional headquarters, interprovincial commands, and the Central Office for South Vietnam (COSVN), the supreme military and political headquarters. As the southern branch of the Vietnamese Communist Party, COSVN was directly subordinate to the Central Committee in Hanoi. Its senior commanders were high-ranking officers of North Vietnam's Army. To equip the growing number of Viet Cong forces in the South, the insurgents continued to rely heavily on arms and supplies captured from South Vietnamese forces. But, increasingly, large numbers of weapons, ammunition, and other equipment arrived from the North, nearly all supplied by the Sino-Soviet bloc.

From a strength of approximately 5,000 at the start of 1959, the Viet Cong's ranks grew to about 100,000 at the end of 1964. The number of infiltrators alone during that period was estimated at 41,000. The growth of the insurgency reflected not only North Vietnam's skill in infiltrating men and weapons, but South Vietnam's inability to control its porous borders, Diem's failure to develop a credible pacification program to reduce Viet Cong influence in the countryside, and the South Vietnamese Army's difficulties in reducing long-standing Viet Cong bases and secret zones. Such areas not only facilitated infiltration, but were staging areas for operations; they contained training camps, hospitals, depots, workshops, and command centers. Many bases were in remote areas seldom visited by the army, such as the U Minh Forest or the Plain of Reeds. But others existed in the heart of populated areas, in the "liberated zones." There Viet Cong forces, dispersed among hamlets and villages, drew support from the local economy. From such centers the Viet Cong expanded their influence into adjacent areas that were nominally under Saigon's control.

Soon after John F. Kennedy became President in 1961, he sharply increased military and economic aid to South Vietnam to help Diem defeat the growing insurgency. For Kennedy, insurgencies (or "wars of national liberation" in the parlance of Communist leaders) was a challenge to international security every bit as serious as nuclear war. The administration's approach to both extremes of conflict rested on the precepts of the flexible response. Regarded as a form of "sub-limited" or small war, insurgency was treated largely as a military problem-conventional war writ small-and hence susceptible to resolution by timely and appropriate military action. Kennedy's success in applying calculated military pressures to compel the Soviet Union to remove its offensive missiles from Cuba in 1962 reinforced the administration's disposition to deal with other international crises, including the conflict in Vietnam, in a similar manner.

Though an advance over the New Look, his policy also had limitations. Long-term strategic planning tended to be sacrificed to short-term crisis management. Planners were all too apt to assume that all belligerents were rational and that the foe subscribed as they did to the seductive logic of the flexible response. Hoping to give the South Vietnamese a margin for success Kennedy periodically authorized additional military aid and support between I96I and November 1963, when he was assassinated. But potential benefits were nullified by the absence of a clear doctrine and a coherent operational strategy for the conduct of counterinsurgency, and by chronic military and political shortcomings on the part of the South Vietnamese.

The U.S. Army played a major role in Kennedy's "beef up" of the American advisory and support efforts in South Vietnam. In turn, that role was made possible in large measure by Kennedy's determination to increase the strength and capabilities of Army forces for both conventional and unconventional operations. Between 1961 and 1964 the Army's strength rose from about 850,000 to nearly a million men, and the number of combat divisions grew from eleven to sixteen. These increases were backed up by an ambitious program to modernize Army equipment and, by stockpiling supplies and equipment at forward bases, to increase the deployability and readiness of Army combat forces. The build-up, however, did not prevent the call-up of 120,000 Reservists to active duty in the summer of 1961, a few months after Kennedy assumed office. Facing renewed Soviet threats to force the Western Powers out of Berlin, Kennedy mobilized the Army to reinforce NATO, if need be. But the mobilization revealed serious shortcomings in Reserve readiness and produced a swell of criticism and complaints from Congress and Reservists alike. Although Kennedy sought to remedy the deficiencies that were exposed and set in motion plans to reorganize the Reserves, the unhappy experience of the Berlin Crisis was fresh in the minds of national leaders when they faced the prospect of war in Vietnam a few years later.

Facing trouble spots in Latin America, Africa, and Southeast Asia, Kennedy took a keen interest in the U.S. Army's Special Forces, believing that their skills in unconventional warfare were well suited to countering insurgency. During his first year in office, he increased the strength of the Special Forces from about 1,500 to 9,000 and authorized them to wear a distinctive Green Beret. In the same year he greatly enlarged their role in South Vietnam. First under the auspices of the Central Intelligence Agency and then under a military commander, the Special Forces organized the highland tribes into the Civilian Irregular Defense Group (CIDG) and in time sought to recruit other ethnic groups and sects in the South as well. To this scheme, underwritten almost entirely by the United States, Diem gave only tepid support. Indeed, the civilian irregulars drew strength from groups traditionally hostile to Saigon. Treated with disdain by the lowland Vietnamese, the Montagnards developed close, trusting relations with their Army advisers. Special Forces detachment commanders frequently were the real leaders of CIDG units. This strong mutual bond of loyalty between adviser and highlander benefited operations, but some tribal leaders sought to exploit the special relationship to advance Montagnard political autonomy. On occasion, Special Forces advisers found themselves in the awkward position of mediating between militant Montagnards and South Vietnamese officials who were suspicious and wary of the Americans' sympathy for the highlanders.

Through a village self-defense and development program, the Special Forces aimed initially to create a military and political buffer to the growing Viet Cong influence in the Central Highlands. Within a few years, approximately 60,000 highlanders had enlisted in the CIDG program. As their participation increased, so too did the range of Special Forces activities. In addition to village defense programs, the Green Berets sponsored offensive guerrilla activities and border surveillance and control measures. To detect and impede the Viet Cong, camps were established astride infiltration corridors and near enemy base areas, especially along the Cambodian and Laotian borders. But the camps themselves were vulnerable to enemy attack and, despite their presence, infiltration continued. At times, border control diverted tribal units from village defense, the original heart of the CIDG program.

By 1965, as the military situation in the highlands worsened, many CIDG units had changed their character and begun to engage in quasi-conventional military operations. In some instances, irregulars under the leadership of Army Special Forces stood up to crack enemy regiments, offering much of the military resistance to enemy efforts to dominate the highlands. Yet the Special Forces-despite their efforts in South Vietnam and in Laos, where their teams helped to train and advise anti-Communist Laotian forces in the early 1960'S-did not provide an antidote to the virulent insurgency in Vietnam. Long-standing animosities between Montagnard and Vietnamese prevented close, continuing co-operation between the South Vietnamese Army and the irregulars. Long on promises but short on action to improve the lot of the Montagnards, successive South Vietnamese regimes failed to win the loyalty of the tribesmen. And the Special Forces usually operated in areas that were remote from the main Viet Cong threat to the heavily populated and economically important Delta and coastal regions of the country.

Besides the Special Forces, the Army's most important contribution to the fight was the helicopter. Neither Kennedy nor the Army anticipated the rapid growth of aviation in South Vietnam when the first helicopter transportation company arrived in December 1961. Within three years, however, each of South Vietnam's divisions and corps was supported by Army helicopters, with the faster, more reliable and versatile UH-1 (Huey) replacing the older CH-21. In addition to transporting men and supplies, helicopters were used to reconnoiter, to evacuate wounded, and to provide command and control. The Vietnam conflict became the crucible in which Army airmobile and air assault tactics evolved. As armament was added-first machine gun-wielding door-gunners, and later rockets and mini-guns-armed helicopters began to protect troop carriers against antiaircraft fire, to suppress enemy fire around landing zones during air assaults, and to deliver fire support to troops on the ground.

Army fixed-wing aircraft also flourished. Equipped with a variety of detection devices, the OV-1 Mohawk conducted day and night surveillance of Viet Cong bases and trails. The Caribou, with its sturdy frame and ability to land and take off on short, unimproved airfields, proved ideal to supply remote camps.

Army aviation revived old disagreements with the Air Force over the roles and missions of the two services and the adequacy of Air Force close air support. The expansion of the Army's own "air force" nevertheless continued, abetted by the Kennedy administration's interest in extending airmobility to all types of land warfare, from counterinsurgency to the nuclear battlefield. Secretary of Defense Robert S. McNamara himself encouraged the Army to test an experimental air assault division. During 1963 and 1964 the Army demonstrated that helicopters could successfully replace ground vehicles for mobility and provide fire support in lieu of ground artillery. The result was the creation in 1965 of the 1st Cavalry Division (Airmobile)-the first such unit in the Army. In South Vietnam the helicopter's effect on organization and operations was as sweeping as the influence of mechanized forces in World War II. Many of the operational concepts of airmobility, rooted in cavalry doctrine and operations, were pioneered by helicopter units between 1961 and 1964, and later adopted by the new airmobile division and by all Army combat units that fought in South Vietnam.

In addition to Army Special Forces and helicopters, Kennedy greatly expanded the entire American advisory effort. Advisers were placed at the sector (provincial) level and were permanently assigned to infantry battalions and certain lower echelon combat units; additional intelligence advisers were sent to South Vietnam. Wide use was made of temporary training teams in psychological warfare, civic action, engineering, and a variety of logistical functions. With the expansion of the advisory and support efforts came demands for better communications, intelligence, and medical, logistical, and administrative support, all of which the Army provided from its active forces, drawing upon skilled men and units from U.S.-based forces. The result was a slow, steady erosion of its capacity to meet worldwide contingency obligations. But if Vietnam depleted the Army, it also provided certain advantages. The war was a laboratory in which to test and evaluate new equipment and techniques applicable to counterinsurgency-among others, the use of chemical defoliants and herbicides, both to remove the jungle canopy that gave cover to the guerrillas and to destroy his crops. As the activities of all the services expanded, U.S. military strength in South Vietnam increased from under 700 at the start of 1960 to almost 24,000 by the end of 1964. Of these, 15,000 were Army and a little over 2,000 were Army advisers.

Changes in American command arrangements attested to the growing commitment. In February 1962 the Joint Chiefs of Staff established the United States Military Assistance Command, Vietnam (USMACV), in Saigon as the senior American military headquarters in South Vietnam, and appointed General Paul D. Harkins as commander (COMUSMACV). Harkins reported to the Commander in Chief, Pacific (CINCPAC), in Hawaii, but because of high-level interest in South Vietnam, enjoyed special access to military and civilian leaders in Washington as well. Soon MACV moved into the advisory effort hitherto directed by the Military Assistance Advisory Group. To simplify the advisory chain of command, the latter was disestablished in May 1964, and MACV took direct control. As the senior Army commander in South Vietnam, the MACV commander also commanded Army support units; for day-to-day operations, however, control of such units was vested in the corps and division senior advisers. For administrative and logistical support Army units looked to the U.S. Army Support Group, Vietnam (later the U.S. Army Support Command), which was established in mid-1962.

Though command arrangements worked tolerably well, complaints were heard in and out of the Army. Some officials pressed for a separate Army component commander, who would be responsible both for operations and for logistical support-an arrangement enjoyed by other services in South Vietnam. Airmen tended to believe that an Army command already existed, disguised as MACV. They believed that General Harkins, though a joint commander, favored the Army in the bitter interservice rivalry over the roles and missions of aviation in South Vietnam. Some critics thought his span of control excessive, for Harkins' responsibility extended to Thailand, where Army combat units had deployed in 1962, aiming to overawe Communist forces in neighboring Laos. The Army undertook several logistical projects in Thailand, and Army engineers, signalmen, and other support forces remained there after combat forces withdrew in the fall of 1962.

While the Americans strengthened their position in South Vietnam and Thailand, the Communists tightened their grip in Laos. In 1962 agreements on that small, land-locked nation were signed in Geneva requiring all foreign military forces to leave Laos. American advisers, including hundreds of Special Forces, departed. But the agreements were not honored by North Vietnam. Its army, together with Laotian Communist forces, consolidated their hold on areas adjacent to both North and South Vietnam through which passed the network of jungle roads called the Ho Chi Minh Trail. As a result, it became easier to move supplies south to support the Viet Cong in the face of the new dangers embodied in U.S. advisers, weapons, and tactics.

At first the enhanced mobility and firepower afforded the South Vietnamese Army by helicopters, armored personnel carriers, and close air support surprised and overwhelmed the Viet Cong. Saigon's forces reacted more quickly to insurgent attacks and penetrated many Viet Cong areas. Even more threatening to the insurgents was Diem's strategic hamlet program, launched in late 1961. Diem and his brother Ngo Dinh Nhu, an ardent sponsor of the program, hoped to create thousands of new, fortified villages, often by moving peasants from their existing homes. Hamlet construction and defense were the responsibility of the new residents, with paramilitary and ARVN forces providing initial security while the peasants were recruited and organized. As security improved, Diem and Nhu hoped to enact social, economic, and political reforms which, when fully carried out, would constitute Saigon's revolutionary response to Viet Cong promises of social and economic betterment. If successful, the program might destroy the insurgency by separating and protecting the rural population from the Viet Cong, threatening the rebellion's base of support.

By early 1963, however, the Viet Cong had learned to cope with the army's new weapons and more aggressive tactics and had begun a campaign to eliminate the strategic hamlets. The insurgents became adept at countering helicopters and slow-flying aircraft and learned the vulnerabilities of armored personnel carriers. In addition, their excellent intelligence, combined with the predictability of ARVN's tactics and pattern of operations, enabled the Viet Cong to evade or ambush government forces. The new weapons the United States had provided the South Vietnamese did not compensate for the stifling influence of poor leadership, dubious tactics, and inexperience. The much publicized defeat of government forces at the Delta village of Ap Bac in January 1963 demonstrated both the Viet Cong's skill in countering ARVN's new capabilities and the latter's inherent weaknesses. Faulty intelligence, poorly planned and executed fire support, and overcautious leadership contributed to the outcome. But Ap Bac's significance transcended a single battle. The defeat was a portent of things to come. Now able to challenge ARVN units of equal strength in quasi-conventional battles, the Viet Cong were moving into a more intense stage of revolutionary war.

As the Viet Cong became stronger and bolder, the South Vietnamese Army became more cautious and less offensive-minded. Government forces became reluctant to respond to Viet Cong depredations in the countryside, avoided night operations, and resorted to ponderous sweeps against vague military objectives, rarely making contact with their enemies. Meanwhile, the Viet Cong concentrated on destroying strategic hamlets, showing that they considered the settlements, rather than ARVN forces, the greater danger to the insurgency. Poorly defended hamlets and outposts were overrun or subverted by enemy agents who infiltrated with peasants arriving from the countryside.

The Viet Cong's campaign was aided by Saigon's failures. The government built too many hamlets to defend. Hamlet militia varied from those who were poorly trained and armed to those who were not trained or armed at all. Fearing that weapons given to the militia would fall to the Viet Cong, local officials often withheld arms. Forced relocation, use of forced peasant labor to construct hamlets, and tardy payment of compensation for relocation were but a few reasons why peasants turned against the program. Few meaningful reforms took place. Accurate information on the program's true condition and on the decline in rural security was hidden from Diem by officials eager to please him with reports of progress. False statistics and reports misled U.S. officials, too, about the progress of the counterinsurgency effort.

If the decline in rural security was not always apparent to Americans, the lack of enlightened political leadership on the part of Diem was all too obvious. Diem habitually interfered in military matters-bypassing the chain of command to order operations, forbidding commanders to take casualties, and appointing military leaders on the basis of political loyalty rather than competence. Many military and civilian appointees, especially province and district chiefs, were dishonest and put career and fortune above the national interest. When Buddhist opposition to certain policies erupted into violent antigovernment demonstrations in 1963, Diem's uncompromising stance and use of military force to suppress the demonstrators caused some generals to decide that the President was a liability in the fight against the Viet Cong. On 1 November, with American encouragement, a group of reform-minded generals ousted Diem, who was murdered along with his brother.

Political turmoil followed the coup. Emboldened, the insurgents stepped up operations and increased their control over many rural areas. North Vietnam's leaders decided to intensify the armed struggle, aiming to demoralize the South Vietnamese Army and further undermine political authority in the South. As Viet Cong military activity quickened, regular North Vietnamese Army units began to train for possible intervention in the war. Men and equipment continued to flow down the Ho Chi Minh Trail, with North Vietnamese conscripts replacing the dwindling pool of southerners who had belonged to the Viet Minh.

The critical state of rural security that came to light after Diem's death again prompted the United States to expand its military aid to Saigon. General Harkins and his successor General William C. Westmoreland urgently strove to revitalize pacification and counterinsurgency. Army advisers helped their Vietnamese counterparts to revise national and provincial pacification plans. They retained the concept of fortified hamlets as the heart of a new national counterinsurgency program, but corrected the old abuses, at least in theory. To help implement the program, Army advisers were assigned to the subsector (district) level for the first time, becoming more intimately involved in local pacification efforts and in paramilitary operations. Additional advisers were assigned to units and training centers, especially those of the Regional and Popular Forces (formerly called the Civil Guard and Self-Defense Corps). All Army activities, from aviation support to Special Forces, were strengthened in a concerted effort to undo the effects of years of Diem's mismanagement.

At the same time, American officials in Washington, Hawaii, and Saigon began to explore ways to increase military pressure against North Vietnam. In 1964 the South Vietnamese launched covert raids under MACV's auspices. Some military leaders, however, believed that only direct air strikes against North Vietnam would induce a change in Hanoi's policies by demonstrating American determination to defend South Vietnam's independence. Air strike plans ranged from immediate massive bombardment of military and industrial targets to gradually intensifying attacks spanning several months.

The interest in using air power reflected lingering sentiment in the United States against involving American ground forces once again in a land war on the Asian continent. Many of President Lyndon B. Johnson's advisers-among them General Maxwell D. Taylor, who was appointed Ambassador to Saigon in mid-1964-believed that a carefully calibrated air campaign would be the most effective means of exerting pressure against the North and, at the same time, the method least likely to provoke intervention by China. Taylor thought conventional Army ground forces ill suited to engage in day-to-day counterinsurgency operations against the Viet Cong in hamlets and villages. Ground forces might, however, be used to protect vital air bases in the South and to repel any North Vietnamese attack across the demilitarized zone, which separated North from South Vietnam. Together, a more vigorous counterinsurgency effort in the South and military pressure against the North might buy time for Saigon to put its political house in order, boost flagging military and civilian morale, and strengthen its military position in the event of a negotiated peace. Taylor and Westmoreland, the senior U.S. officials in South Vietnam, agreed that Hanoi was unlikely to change its course unless convinced that it could not succeed in the South. Both recognized that air strikes were neither a panacea nor a substitute for military efforts in the South.

As each side undertook more provocative military actions, the likelihood of a direct military confrontation between North Vietnam and the United States increased. The crisis came in early August 1964 in the international waters of the Gulf of Tonkin. North Vietnamese patrol boats attacked U.S. naval vessels engaged in surveillance of North Vietnam's coastal defenses. The Americans promptly launched retaliatory air strikes. At the request of President Johnson, Congress overwhelmingly passed the Southeast Asia Resolution-the so-called Gulf of Tonkin Resolution-authorizing all actions necessary to protect American forces and to provide for the defense of the nation's allies in Southeast Asia. Considered by some in the administration as the equivalent of a declaration of war, this broad grant of authority encouraged Johnson to expand American military efforts within South Vietnam, against North Vietnam, and in Southeast Asia at large.

By late 1964, both sides were poised to increase their stake in the war. Regular NVA units had begun moving south and stood at the Laotian frontier, on the threshold of crossing into South Vietnam's Central Highlands. U.S. air and naval forces stood ready to renew their attacks. On 7 February 1965, Communist forces attacked an American compound in Pleiku in the Central Highlands and a few days later bombed American quarters in Qui Nhon. The United States promptly bombed military targets in the North. A few weeks later, President Johnson approved ROLLING THUNDER, a campaign of sustained, direct air strikes of progressively increasing strength against military and industrial targets in North Vietnam. Signs of intensifying conflict appeared in South Vietnam as well. Strengthening their forces at all echelons, from village guerrillas to main force regiments, the Viet Cong quickened military activity in late 1964 and in the first half of 1965. At Binh Gia, a village forty miles east of Saigon in Phuoc Tuy Province, a multiregimental Viet Cong force-possibly the 1st Viet Cong Infantry Division-fought and defeated several South Vietnamese battalions.

Throughout the spring the Viet Cong sought to disrupt pacification and oust the government from many rural areas. The insurgents made deep inroads in the central coastal provinces and withstood government efforts to reduce their influence in the Delta and in the critical provinces around Saigon. Committed to static defense of key towns and bases, government forces were unable or unwilling to respond to attacks against rural communities. In late spring and early summer, strong Communist forces sought a major military victory over the South Vietnamese Army by attacking border posts and highland camps. The enemy also hoped to draw government forces from populated areas, to weaken pacification further. By whipsawing war-weary ARVN forces between coast and highland and by inflicting a series of damaging defeats against regular units, the enemy hoped to undermine military morale and popular confidence in the Saigon government. And by accelerating the dissolution of government military forces, already racked by high desertions and casualties, the Communists hoped to compel the South Vietnamese to abandon the battlefield and seek an all-Vietnamese political settlement that would compel the United States to leave South Vietnam.

By the summer of 1965, the Viet Cong, strengthened by several recently infiltrated NVA regiments, had gained the upper hand over government forces in some areas of South Vietnam. With U.S. close air support and the aid of Army helicopter gunships, Saigon's forces repelled many enemy attacks, but suffered heavy casualties. Elsewhere highland camps and border outposts had to be abandoned. ARVN's cumulative losses from battle deaths and desertions amounted to nearly a battalion a week. Saigon was hard pressed to find men to replenish these heavy losses and completely unable to match the growth of Communist forces from local recruitment and infiltration. Some American officials doubted whether the South Vietnamese could hold out until ROLLING THUNDER created pressures sufficiently strong to convince North Vietnam's leaders to reduce the level of combat in the South. General Westmoreland and others believed that U.S. ground forces were needed to stave off an irrevocable shift of the military and political balance in favor of the enemy.

For a variety of diplomatic, political, and military reasons, President Johnson approached with great caution any commitment of large ground combat forces to South Vietnam. Yet preparations had been under way for some time. In early March 1965, a few days after ROLLING THUNDER began, American marines went ashore in South Vietnam to protect the large airfield at Da Nang-a defensive security mission. Even as they landed, General Harold K. Johnson, Chief of Staff of the Army, was in South Vietnam to assess the situation. Upon returning to Washington, he recommended a substantial increase in American military assistance, including several combat divisions. He wanted U.S. forces either to interdict the Laotian panhandle to stop infiltration or to counter a growing enemy threat in the central and northern provinces.

But President Johnson sanctioned only the dispatch of additional marines to increase security at Da Nang and to secure other coastal enclaves. He also authorized the Army to begin deploying nearly 20,000 logistical troops, the main body of the 1st Logistical Command, to Southeast Asia. (Westmoreland had requested such a command in late 1964.) At the same time, the President modified the marines' mission to allow them to conduct offensive operations close to their bases. A few weeks later, to protect American bases in the vicinity of Saigon, Johnson approved sending the first Army combat unit, the 173d Airborne Brigade (Separate), to South Vietnam. Arriving from Okinawa in early May, the brigade moved quickly to secure the air base at Bien Hoa, just northeast of Saigon. With its arrival, U.S. military strength in South Vietnam passed 50,000. Despite added numbers and expanded missions, American ground forces had yet to engage the enemy in full-scale combat.

Indeed, the question of how best to use large numbers of American ground forces was still unresolved on the eve of their deployment. Focusing on population security and pacification, some planners saw U.S. combat forces concentrating their efforts in coastal enclaves and around key urban centers and bases. Under this plan, such forces would provide a security shield behind which the Vietnamese could expand the pacification zone; when required, American combat units would venture beyond their enclaves as mobile reaction forces.

This concept, largely defensive in nature, reflected the pattern established by the first Army combat units to enter South Vietnam. But the mobility and offensive firepower of U.S. ground units suggested their use in remote, sparsely populated regions to seek out and engage main force enemy units as they infiltrated into South Vietnam or emerged from their secret bases. While secure coastal logistical enclaves and base camps still would be required, the weight of the military effort would be focused on the destruction of enemy military units. Yet even in this alternative, American units would serve indirectly as a shield for pacification activities in the more heavily populated lowlands and Delta. A third proposal had particular appeal to General Johnson. He wished to employ U.S. and allied ground forces across the Laotian panhandle to interdict enemy infiltration into South Vietnam. Here was a more direct and effective way to stop infiltration than the use of air power. Encumbered by military and political problems, the idea was revived periodically but always rejected. The pattern of deployment that actually developed in South Vietnam was a compromise between the first two concepts.

For any type of operations, secure logistical enclaves at deep-water ports (Cam Ranh Bay, Nha Trang, Qui Nhon, for example) were a military necessity. In such areas combat units arrived and bases developed for regional logistical complexes to support the troops. As the administration neared a decision on combat deployment, the Army began to identify and ready units for movement overseas and to prepare mobilization plans for Selected Reserve forces. The dispatch of Army units to the Dominican Republic in May 1965 to forestall a leftist take-over caused only minor adjustments to the build-up plans. The episode nevertheless showed how unexpected demands elsewhere in the world could deplete the strategic reserve, and it underscored the importance of mobilization if the Army was to meet worldwide contingencies and supply trained combat units to Westmoreland as well.

The prospect of deploying American ground forces also revived discussions of allied command arrangements. For a time, Westmoreland considered placing South Vietnamese and American forces under a single commander, an arrangement similar to that of U.S. and South Korean forces during the Korean War. In the face of South Vietnamese opposition, however, the idea was dropped. Arrangements with other allies were varied. Americans in South Vietnam were joined by combat units from Australia, New Zealand, South Korea, Thailand, and by noncombat elements from several other nations. Westmoreland entered into separate agreements with each commander in turn; the compacts ensured close co-operation with MACV, but fell short of giving Westmoreland command over the allied forces.

While diversity marked these arrangements, Westmoreland strove for unity within the American build-up. As forces began to deploy to South Vietnam, the Army again sought to elevate the U.S. Army, Vietnam (USARV), to a full-fledged Army component command with responsibility for combat operations. But Westmoreland successfully warded off the challenge to his dual role as unified commander of MACV and Army commander. For the remainder of the war, USARV performed solely in a logistical and administrative capacity; unlike MACV's air and naval component commands, the Army component did not exercise operational control over combat forces, special forces, or field advisers. However, through its logistical, engineer, signal, medical, military police, and aviation commands all established in the course of the build-up, USARV commanded and managed a support base of unprecedented size and scope.

Despite this victory, unity of command over the ground war in South Vietnam eluded Westmoreland, as did over-all control of U.S. military operations in support of the war. Most air and naval operations outside of South Vietnam, including ROLLING THUNDER, were carried out by the Commander in Chief, Pacific, and his air and naval commanders from his headquarters thousands of miles away in Hawaii. This patchwork of command arrangements contributed to the lack of a unified strategy, the fragmentation of operations, and the pursuit of parochial service interests to the detriment of the war effort. No single American commander had complete authority or responsibility to fashion an over-all strategy or to co-ordinate all military aspects of the war in Southeast Asia. Furthermore, Westmoreland labored under a variety of political and operational constraints on the use of the combat forces he did command. Like the Korean War, the struggle in South Vietnam was complicated by enemy sanctuaries and by geographical and political restrictions on allied operations. Ground forces were barred from operating across South Vietnam's borders into Cambodia, Laos, or North Vietnam, although the border areas of those countries were vital to the enemy's war effort. These factors narrowed Westmoreland's freedom of action and detracted from his efforts to make effective use of American military power.

On 28 July 1965, President Johnson announced plans to deploy additional combat units and to increase American military strength in South Vietnam to 175,000 by year's end. The Army already was preparing hundreds of units for duty in Southeast Asia, among them the newly activated 1st Cavalry Division (Airmobile). Other combat units-the 1st Brigade, 101st Airborne Division, and all three brigades of the 1st Infantry Division-were either ready to go or already on their way to Vietnam. Together with hundreds of support and logistical units, these combat units constituted the first phase of the build-up during the summer and fall of 1965.

At the same time, President Johnson decided not to mobilize any Reserve units. The President's decision profoundly affected the manner in which the Army supported and sustained the build-up. To meet the call for additional combat forces and to obtain manpower to enlarge its training base and to maintain a pool for rotation and replacement of soldiers in South Vietnam, the Army had to increase its active strength, over the next three years, by nearly 1.5 million men. Necessarily, it relied on larger draft calls and voluntary enlistments, supplementing them with heavy draw downs of experienced soldiers from units in Europe and South Korea and extensions of some tours of duty to retain specialists, technicians, and cadres who could train recruits or round out deploying units. Combat units assigned to the strategic reserve were used to meet a large portion of MACV's force requirements, and Reservists were not available to replace them. Mobilization could have eased the additional burden of providing noncommissioned officers (NCO's) and officers to man the Army's growing training bases. As matters stood, pacification program. In June 1965 the last in a series of coups that followed Diem's overthrow brought in a military junta headed by Lt. Gen. Nguyen Van Thieu as Chief of State and Air Vice Marshal Nguyen Cao Ky as Prime Minister. The new government provided the political stability requisite for successful pacification. Success hinged also on the ability of the U.S. air campaign against the North to reduce the infiltration of men and material, dampening the intensity of combat in the South and inducing Communist leaders in Hanoi to alter their long-term strategic goals. Should any strand of this threefold strategy-the campaign against Communist forces in the South, Saigon's pacification program, and the air war in the North-falter, Westmoreland's prospects would become poorer. Yet he was directly responsible for only one element, the U.S. military effort in the South. To a lesser degree, through American advice and assistance to the South Vietnamese forces, he also influenced Saigon's efforts to suppress the Viet Cong and to carry out pacification.

Centered on the defense of Saigon, Westmoreland's concept of operations in the III Corps area had a clarity of design and purpose that was not always apparent elsewhere in South Vietnam. Nearly two years would pass before U.S. forces could maintain a security belt around the capital and at the same time attack the enemy's bases. But Westmoreland's ultimate aims and the difficulties he would encounter were both foreshadowed by the initial combat operations in the summer and fall of 1965.

Joined by newly arrived Australian infantrymen, the 173d Airborne Brigade during June began operations in War Zone D, a longtime enemy base north of Saigon. Though diverted several times to other tasks, the brigade gained experience in conducting heliborne assaults and accustomed itself to the rigors of jungle operations. It also established a pattern of operations that was to grow all too familiar. Airmobile assaults, often in the wake of B-52 air strikes, were followed by extensive patrolling, episodic contact with the Viet Cong, and withdrawal after a few days' stay in the enemy's territory. In early November the airborne soldiers uncovered evidence of the enemy's recent and hasty departure-abandoned camps, recently vacated tunnels, and caches of food and supplies. However, the Viet Cong, by observing the brigade, began to formulate plans for dealing with the Americans.

On 8 November, moving deeper into War Zone D, the brigade encountered the first significant resistance. A multibattalion Viet Cong force attacked at close quarters and forced the Americans into a tight defensive perimeter. Hand-to-hand combat ensued as the enemy tried to "hug" American soldiers to prevent the delivery of supporting air and artillery fire. Unable to prepare a landing zone to receive reinforcements or to evacuate casualties, the beleaguered Americans withstood repeated enemy assaults. At nightfall the Viet Cong ceased their attack and withdrew under cover of darkness. Next morning, when reinforcements arrived, the brigade pursued the enemy, finding evidence that he had suffered heavy casualties. Such operations inflicted losses but failed either to destroy the enemy's base or to prevent him from returning to it later on.

Like the airborne brigade, the 1st Infantry Division initially divided its efforts. In addition to securing its base camps north of Saigon, the division helped South Vietnamese forces clear an area west of the capital in the vicinity of Cu Chi in Hau Nghia Province. Reacting to reports of enemy troop concentrations, units of the division launched a series of operations in the fall of 1965 and early 1966 that entailed quick forays into the Ho Bo and Boi Loi woods, the Michelin Rubber Plantation, the Rung Sat swamp, and War Zones C and D. In Operation MASTIFF, for example, the division sought to disrupt Viet Cong infiltration routes between War Zones C and D that crossed the Boi Loi woods in Tay Ninh Province, an area that had not been penetrated by government forces for several years.

But defense of Saigon was the first duty of the "Big Red One" as well as of the 25th Infantry Division, which arrived in the spring of 1966. The 1st Division took up a position protecting the northern approaches, blocking Route 15 from the Cambodian border. The 25th guarded the western approaches, chiefly Route 1 and the Saigon River. The two brigades of the 25th Division served also as a buffer between Saigon and the enemy's base areas in Tay Ninh Province. Westmoreland hoped, however, that the 25th Division would loosen the insurgents' tenacious hold on Hau Nghia Province as well. Here American soldiers found to their amazement that the division's camp at Cu Chi had been constructed atop an extensive Viet Cong tunnel complex. Extending over an area of several miles, this subterranean network, one of several in the region, contained hospitals, command centers, and storage sites. The complex, though partially destroyed by Army "tunnel rats," was never completely eliminated and lasted for the duration of the war. The With Division worked closely with South Vietnamese Army and paramilitary forces throughout 1966 and 1967 to foster pacification in Hau Nghia and to secure its own base. But suppressing insurgency in Hau Nghia proved as difficult as eradicating the tunnels at Cu Chi.

As the number of Army combat units in Vietnam grew larger, Westmoreland established two corps-size commands, I Field Force in the II Corps area and II Field Force in the III Corps area.

Reporting directly to the MACV commander, the field force commander was the senior Army tactical commander in his area and the senior U.S. adviser to ARVN forces there. Working closely with his South Vietnamese counterpart, he co-ordinated ARVN and American operations by establishing territorial priorities for combat and pacification efforts. Through his deputy senior adviser, a position established in 1967, the field force commander was able to keep abreast both of the activities of U.S. sector (province) and subsector (district) advisers and of the progress of Saigon's pacification efforts. A similar arrangement was set up in I Corps, where the commander of the III Marine Amphibious Force was the equivalent of a field force commander. Only in IV Corps, in the Mekong Delta where few American combat units served, did Westmoreland choose not to establish a corps-size command. There the senior U.S. adviser served as COMUSMACV's representative; he commanded Army advisory and support units, but no combat units.

Although Army commanders in III Corps were eager to seek out and engage enemy main force units in their strongholds along the Cambodian border, operations at first were devoted to base and area security and to clearing and rehabilitating roads. The 1st Infantry Division's first major encounter with the Viet Cong occurred in November as division elements carried out a routine road security operation along Route 13, in the vicinity of the village of Bau Bang. Trapping convoys along Route 13 had long been a profitable Viet Cong tactic. Ambushed by a large, well-entrenched enemy force, division troops reacted aggressively and mounted a successful counterattack. But the road was by no means secured; close to enemy bases, the Cambodian border, and Saigon, Route 13 would be the site of several major battles in years to come.

Roads were a major concern of U.S. commanders. In some operations, infantrymen provided security as Army engineers improved neglected routes. Defoliants and the Rome plow-a bulldozer modified with sharp front blades-removed from the sides of important highways the jungle growth that provided cover for Viet Cong ambushes. Road-clearing operations also contributed to pacification by providing peasants with secure access to local markets. In III Corps, with its important road network radiating from Saigon, ground mobility was as essential as airmobility for the conduct of military operations. Lacking as many helicopters as the airmobile division, the 1st and 25th Infantry Divisions, like all Army units in South Vietnam, strained the resources of their own aviation support units and of other Army aviation units providing area support to obtain the maximum airmobile capacity for each operation. Nevertheless, on many occasions the Army found itself road bound.

Road and convoy security was also the original justification for introducing Army mechanized and armor units into South Vietnam in 1966. At first Westmoreland was reluctant to bring heavy mechanized equipment into South Vietnam, for it seemed ill suited either to counterinsurgency operations or to operations during the monsoon season, when all but a few roads were impassable. Armor advocates pressed Westmoreland to reconsider his policy. Operation CIRCLE PINES, carried out by elements of the 25th Infantry Division in the spring of 1966, successfully combined an infantry force and an armor battalion. This experience, together with new studies indicating a greater potential for mechanized forces, led Westmoreland to reverse his original policy and request deployment of the 11th Armored Cavalry Regiment, with its full complement of tanks, to Vietnam.

Arriving in III Corps in the last half of 1966, the regiment set up base at Xuan Loc, on Route I northeast of Saigon in Long Khanh Province. In addition to assuming an area support mission and strengthening the eastern approaches to Saigon as part of Westmoreland's security belt around the capital, squadrons of the regiment supported Army units throughout the corps zone, often "homesteading" with other brigades or divisions.

Route security, however, was only the first step in carving out a larger role for Army mechanized forces. Facing an enemy who employed no armor, American mechanized units, often in conjunction with airmobile assaults, acted both as blocking or holding forces and as assault or reaction forces, where terrain permitted. "Jungle bashing," as offensive armor operations were sometimes called, had its uses but also its limitations. The intimidating presence of tanks and personnel carriers was often nullified by their cumbersomeness and noise, which alerted the enemy to an impending attack. The Viet Cong also took countermeasures to immobilize tracked vehicles. Crude tank traps, locally manufactured mines (often made of plastic to thwart discovery by metal detectors), and well-aimed rocket or recoilless rifle rounds could disable a tank or personnel carrier. Together with the dust and tropical humidity, such weapons placed a heavy burden on Army maintenance units. Yet mechanized units brought the allies enhanced mobility and firepower and often were essential to counter ambushes or destroy an enemy force protected by bunkers.

As Army strength increased in III Corps, Westmoreland encouraged his units to operate farther afield. In early 1966 intelligence reports indicated that enemy strength and activity were increasing in many of his base areas. In two operations during the early spring of 1966, units of the 1st and 25th Divisions discovered Viet Cong training camps and supply dumps, some of the sites honeycombed with tunnels. But they failed to engage major enemy forces. As Army units made the deepest penetration of War Zone C since 1961, all signs pointed to the foe's hasty withdrawal into Cambodia. An airmobile raid failed to locate the enemy's command center, COSVN. (COSVN, in fact, was fragmented among several sites in Tay Ninh Province and in nearby Cambodia.) Like the 173d Airborne Brigade's operations, the new attacks had no lasting effects.

By May 1966 an ominous build-up of enemy forces, among them NVA regiments that had infiltrated south, was detected in Phuoc Long and Binh Long Provinces in northern III Corps. U.S. commanders viewed the build-up as a portent of the enemy's spring offensive, plans for which included an attack on the district town of Loc Ninh and on a nearby Special Forces camp. The 1st Division responded, sending a brigade to secure Route 13. But the threat to Loc Ninh heightened in early June, when regiments of the 9th Viet Cong Division took up positions around the town. The arrival of American reinforcements apparently prevented an assault. About a week later, however, an enemy regiment was spotted in fortified positions in a rubber plantation adjacent to Loc Ninh. Battered by massive air and artillery strikes, the regiment was dislodged and its position overrun, ending the threat. Americans recorded other successes, trapping Viet Cong ambushers in a counterambush, securing Loc Ninh, and spoiling the enemy's spring offensive. But if the enemy still underestimated the mobility and firepower that U.S. commanders could bring to bear, he had learned how easily Americans could be lured away from their base camps.

By the summer of 1966 Westmoreland believed he had stopped the losing trend of a year earlier and could begin the second phase of his general campaign strategy. This entailed aggressive operations to search out and destroy enemy main force units, in addition to continued efforts to improve security in the populated areas of III Corps. In Operation ATTLEBORO he sent the 196th Infantry Brigade and the 3d Brigade, 4th Infantry Division, to Tay Ninh Province to bolster the security of the province seat. Westmoreland's challenge prompted COSVN to send the 9th Viet Cong Division on a "countersweep," the enemy's term for operations to counter allied search and destroy tactics. Moving deeper into the enemy's stronghold, the recently arrived and inexperienced 196th Infantry Brigade sparred with the enemy. Then an intense battle erupted, as elements of the brigade were isolated and surprised by a large enemy force. Operation ATTLEBORO quickly grew to a multidivision struggle as American commanders sought to maintain contact with the Viet Cong and to aid their own surrounded forces. Within a matter of days, elements of the 1st and 25th Divisions, the 173d Airborne Brigade, and the 11th Armored Cavalry Regiment had converged on War Zone C. Control of ATTLEBORO passed in turn from the 25th to the 1st Division and finally to the II Field Force, making it the first Army operation in South Vietnam to be controlled by a corps-size headquarters. With over 22,000 U.S. troops participating, the battle had become the largest of the war. Yet combat occurred most often at the platoon and company levels, usually at night. As the number of American troops increased, the 9th Viet Cong Division shied away, withdrawing across the Cambodian border. Then Army forces departed, leaving to the Special Forces the task of detecting the enemy's inevitable return.

As the threat along the border abated, Westmoreland turned his attention to the enemy's secret zones near Saigon, among them the so-called Iron Triangle in Binh Duong Province. Harboring the headquarters of Military Region IV, the Communist command that directed military and terrorist activity in and around the capital, this stronghold had gone undisturbed for several years. Westmoreland hoped to find the command center, disrupt Viet Cong activity in the capital region, and allow South Vietnamese forces to accelerate pacification and uproot the stubborn Viet Cong political organization that flourished in many villages and hamlets.

Operation CEDAR FALLS began on 8 January 1967 with the objectives of destroying the headquarters, interdicting the movement of enemy forces into the major war zones in III Corps, and defeating Viet Cong units encamped there. Like ATTLEBORO before it, CEDAR FALLS tapped the manpower and resources of nearly every major Army unit in the corps area. A series of preliminary maneuvers brought Army units into position. Several air assaults sealed off the Iron Triangle, exploiting the natural barriers of the rivers that formed two of its boundaries. Then American units began a series of sweeps to push the enemy toward the blocking forces. At the village of Ben Suc, long under the sway of the insurgents, sixty helicopters descended into seven landing zones in less than a minute. Ben Suc was surrounded, its entire population evacuated, and the village and its tunnel complex destroyed. But insurgent forces had fled before the heliborne assault. As CEDAR FALLS progressed, U.S. troops destroyed hundreds of enemy fortifications, captured large quantities of supplies and food, and evacuated other hamlets. Contact with the enemy was fleeting. Most of the Viet Cong, including the high-level cadre of the regional command, had escaped, sometimes infiltrating through allied lines.

By the time Army units left the Iron Triangle, MACV had already received reports that Viet Cong and NVA regiments were returning to War Zone C in preparation for a spring offensive. This time Westmoreland hoped to prevent Communist forces from escaping into Cambodia, as they had done in ATTLEBORO. From forward field positions established during earlier operations, elements of the 25th and 1st Divisions, the 196th Infantry Brigade, and the 11th Armored Cavalry Regiment launched JUNCTION CITY, moving rapidly to establish a cordon around the war zone and to begin a new sweep of the base area. As airmobile and mechanized units moved into positions on the morning of 21 February 1967, elements of the 173d Airborne Brigade made the only parachute drop of the Vietnam War-and the first combat airborne assault since the Korean War-to establish a blocking position near the Cambodian border. Then other U.S. units entered the horseshoe-shaped area of operations through its open end.

Despite the emphasis on speed and surprise, Army units did not encounter many enemy troops at the outset. As the operation entered its second phase, however, American forces concentrated their efforts in the eastern portion of War Zone C, close to Route I3. Here several violent battles erupted, as Communist forces tried to isolate and defeat individual units and possibly also to screen the retreat of their comrades into Cambodia. On I9 March a mechanized unit of the gth Infantry Division was attacked and nearly overrun along Route Is near the battered village of Bau Bang. The combined firepower of armored cavalry, supporting artillery, and close air support finally caused the enemy to break contact. A few days later, at Fire Support Base GOLD, in the vicinity of Soul Tre, an infantry and artillery battalion of the Pith Infantry engaged the 272d Viet Cong Regiment. Behind an intense, walking mortar barrage, enemy troops breached GOLD'S defensive perimeter and rushed into the base.

Man-to-man combat ensued. A complete disaster was averted when Army artillerymen lowered their howitzers and fired, directly into the oncoming enemy, Beehive artillery rounds that contained hundreds of dartlike projectiles. The last major encounter with enemy troops during JUNCTION CITY occurred at the end of March, when elements of two Viet Cong regiments, the 271st and the 70th (the latter directly subordinate to COSVN) attacked a battalion of the 1st Infantry Division in a night defensive position deep in War Zone C, near the Cambodian border. The lopsided casualties-over 600 enemy killed in contrast to 10 Americans-forcefully illustrated once again the U.S. ability to call in overwhelmingly superior fire support by artillery, armed helicopters, and tactical aircraft.
Thereafter, JUNCTION CITY became a pale shadow of the multidivision effort it had been at its outset. Most Army units were withdrawn, either to return to their bases or to participate in other operations. The 196th Infantry Brigade was transferred to I Corps to help replace Marine forces sent north to meet a growing enemy threat near the demilitarized zone. Contacts with enemy forces in this final phase were meager. Again a planned Viet Cong offensive had been aborted; the enemy himself escaped, though not unscathed.

In the wake of JUNCTION CITY, MACV's attention reverted to the still critical security conditions around Saigon. The 1st Infantry Division returned to War Zone D to search for the 271st Viet Cong Regiment and to disrupt the insurgents' lines of communications between War Zones C and D. Despite two major contacts, the main body of the regiment eluded its American pursuers. Army units again returned to the Iron Triangle between April and July 1967, after enemy forces were detected in their old stronghold. Supplies and documents were found in quantities even larger than those discovered in CEDAR FALLS. Once again, however, encounters with the Communists were fleeting. The enemy's reappearance in the Iron Triangle and War Zone D, combined with rocket and mortar attacks on U.S. bases around Saigon, heightened Westmoreland's concern about the security of the capital. When the 1st Infantry Division's base at Phuoc Vinh and the Bien Hoa Air Base were attacked in mid-1967, the division mounted operations into the Ong Dong jungle and the Vinh Loi woods. Other operations swept the jungles and villages of Bien Hoa Province and sought once again to support pacification in Hau Nghia Province.

These actions pointed up a basic problem. The large, multidivision operations into the enemy's war zones produced some benefits for the pacification campaign; by keeping enemy main force regiments at bay, Westmoreland impeded their access to heavily populated areas and prevented them from reinforcing Viet Cong provincial and district forces. Yet when American units were shifted to the border, the local Viet Cong units gained a measure of relief Westmoreland faced a strategic dilemma: he could not afford to keep substantial forces away from their bases for more than a few months at a time without jeopardizing local security. Unless he received additional forces, Westmoreland would always be torn between two operational imperatives. By the summer of 1967, MACV's likelihood of receiving more combat troops, beyond those scheduled to deploy during the latter half of the year and in early 1968, had become remote. In Washington the administration turned down his request for an additional 200,000 men.

Meanwhile, however, the 9th Infantry Division and the 199th Infantry Brigade arrived in South Vietnam. Westmoreland stationed the brigade at Bien Hoa, where it embarked on FAIRFAX, a year-long operation in which it worked closely with a South Vietnamese ranger group to improve security in Gia Dinh Province, which surrounded the capital. Units of the brigade "paired off,' with South Vietnamese rangers and, working closely with paramilitary and police forces, sought to uproot the very active Viet Cong local forces and destroy the enemy's political infrastructure. Typical activities included ambushes by combined forces; cordon and search operations in villages and hamlets, often in conjunction with the Vietnamese police; psychological and civic action operations; surprise road blocks to search for contraband and Viet Cong supporters; and training programs to develop proficient military and local self-defense capabilities.

Likewise, the 9th Infantry Division set up bases east and south of Saigon. One brigade deployed to Bear Cat; another set up camp at Tan An in Long An Province, south of Saigon, where it sought to secure portions of Route 4, an important north-south highway connecting Saigon with the rice-rich lower Delta. Further south, the 2d Brigade, 9th Infantry Division, established its base at Dong Tam in Dinh Tuong Province in IV Corps. Located in the midst of rice paddies and swamps, Dong Tam was created by Army engineers with sand dredged from the My Tho River. From this 600-acre base, the brigade began a series of riverine operations unique to the Army's experience in South Vietnam.

To patrol and fight in the inundated marshlands and rice paddies and along the numerous canals and waterways crossing the Delta, the Army modernized the concept of riverine warfare employed during the Civil War by Union forces on the Mississippi River and by the French during the Indochina War. The Mobile Riverine Force utilized a joint Army-Navy task force controlled by a ground commander. In contrast to amphibious operations, where control reverts to the ground commander only after the force is ashore, riverine warfare was an extension of land combat, with infantry units traveling by water rather than by trucks or tracked vehicles. Aided by a Navy river support squadron and river assault squadron, infantrymen were housed on barracks ships and supported by gunships or fire support boats called monitors. Howitzers and mortars mounted on barges provided artillery support. The ad Brigade, 9th Infantry Division, began operations against the Cam Son Secret Zone, approximately 10 miles west of Dong Tam, in May 1967.

Meanwhile, the war of main force units along the borders waxed and waned in relation to seasonal weather cycles, which affected the enemy's pattern of logistical activity, his ability to infiltrate men and supplies from North Vietnam, and his penchant for meticulous preparation of the battlefield. By the fall of 1967, enemy activity had increased again in the base areas, and sizable forces began appearing along South Vietnam's border from the demilitarized zone to III Corps. By the year's end, American forces had returned to War Zone C to screen the Cambodian border to prevent Communist forces from re-entering South Vietnam. Units of the 25th Infantry Division that had been conducting operations in the vicinity of Saigon moved to the border. Elements of the 1st Infantry Division had resumed road-clearing operations along Route I3, but the division soon faced another major enemy effort to capture Loc Ninh. On 29 October Viet Cong units assaulted the CIDG camp and the district command post, breaching the defense perimeter. Intense air and artillery fire prevented its complete loss. Within a few hours, South Vietnamese and U.S. reinforcements reached Loc Ninh, their arrival made possible by the enemy's failure to capture the local airstrip.

When the build-up ended, ten Army battalions were positioned within Loc Ninh and between the town and the Cambodian border. During the next two days allied units warded off repeated enemy attacks as Communist forces desperately tried to score a victory. Tactical air support and artillery fire prevented the enemy from massing though he outnumbered allied forces by about ten to one. At the end of a ten-day battle, over 800 enemy were left on the battlefield, while allied deaths numbered only 50. Some 452 close air support sorties, 8 B-52 bomber strikes, and 30,125 rounds of artillery had been directed at the enemy. Once again, Loc Ninh had served as a lightning rod to attract U.S. forces to the border. The pattern of two wars-one in the villages, one on the border-continued without decision.