Joint warfare in South Vietnam 1964-1968

A new situation arose due to the overthrow of Diem, the two coups shortly following, the Gulf of Tonkin incident, and increasing intensity in the war.

Note that Minh was exiled within the same month as the Gulf of Tonkin incident, with its obvious ramifications of increased U.S. involvement.

Roughly until mid-1965, the SVN-US strategy still focused around strategic hamlets, but

1964

September 1964: SVN explores governments

Under Khanh, the start of a civilian government, called the High Legislative Council, started in September, with Pham Khac Suu as head of state and Tran Van Huong as Premier and head of government. INR, however, did not believe this council would gain traction unless it was perceived as representative by both the populace and the military. Khanh dissolved the council in December, in the face of new demonstrations, although he temporarily retain Suu and Huong, dismissing them in December. Khanh, according to INR, created a new tension with the Buddhists that Huong had not, and also may have been approaching Hanoi much as he had accused Minh.

1965

February 1965: new government in Saigon; U.S. intensifies air operations

A coup against Khanh failed in early February, but he left the country within a few weeks, with the Armed Forces Council back in charge. Just before Khanh left, the Council did set up a new civilian government headed by Phan Huy Quat. INR saw the Quat government as evidence of a temporary stability between the military and the Buddhist, but one that could be broken by a power play of factions on either side.

Under Khanh, the start of a civilian government, called the High Legislative Council, started in September, with Pham Khac Suu as head of state and Tran Van Huong as Premier and head of government. INR, however, did not believe this council would gain traction unless it was perceived as representative by both the populace and the military. Khanh dissolved the council in December, in the face of new demonstrations, although he temporarily retain Suu and Huong, dismissing them in December. Khanh, according to INR, created a new tension with the Buddhists that Huong had not, and also may have been approaching Hanoi much as he had accused Minh.

A coup against Khanh failed in early February, but he left the country within a few weeks, with the Armed Forces Council back in charge. Just before Khanh left, the Council did set up a new civilian government headed by Phan Huy Quat. INR saw the Quat government as evidence of a temporary stability between the military and the Buddhist, but one that could be broken by a power play of factions on either side.

On February 6, the VC attacked U.S. facilties at Pleiku, killing 8 and destroying 10 aircraft. President Johnson, on February 7-8, responded with the first specifically retaliatory air raid, Operation FLAMING DART (or, more specifically, FLAMING DART I), of the broader Operation ROLLING THUNDER plan, which had not yet officially started.

The Pleiku attack seems to have been a vital decision point for the U.S. While the introduction of U.S. ground troops had been discussed for years, there were no specific plans. Bundy's memorandum to Johnson about the attack, on 7 February, did not propose the introduction of combat troops.

Johnson made no public announcements, although the U.S. press reported it. The attack was carried out by U.S. Navy aviators from an aircraft carrier in the South China Sea. FLAMING DART II was a response to an attack on Qui Nhon on March 10. In response, initially unknown to the U.S., the North Vietnamese received their first S-75 Dvina (NATO reporting name SA-2 GUIDELINE) surface-to-air missiles, starting an upward spiral of air attack and air defense.

It must be emphasized that for most of the war, the bulk of the attacks on the North came, at first, from Navy carriers offshore. When the bombing escalated, they were joined by U.S. Air Force fighter-bombers flying from bases in Thailand. While there were occasional strikes on the DMZ and the southern part of the DRV from bases in the South, especially when South Vietnamese aircraft participated, the U.S. bases in the RVN primarily supported operations there. Da Nang was the primary South Vietnamese base for such strikes.

Bases in SVN, however, were accessible to the VC, by ground attack, or with rockets and mortars of only a few miles' range. As FLAMING DART progressed and the detailed planning for the major air escalation of ROLLING THUNDER, Westmoreland was concerned about the security of the exposed U.S. air bases in the south. On February 22, he sent his deputy, LTG John Throckmorton, to inspect the Marine aviation base at Da Nang; Throckmorton reported that a full Marine Expeditionary Brigade, with three infantry battalions and supporting elements, were needed to ensure its defense. Westmoreland, according to Davidson, believed a two-battalion MEB was more politically acceptable, but submitted that request.

Ambassador Taylor, a retired general with extensive combat experience, objected. His calculation was that one battalion would protect the base from any plausible direct VC ground attack, but that six, not three, battalions would be necessary to establish a sufficiently large area to prevent the VC firing on Da Nang with standard and easily portable 81mm mortars.

Johnson approved sending two Marine battalions on February 26. Other than possibly Westmoreland, they were seen purely as defensive troops. Westmoreland denies assuming they would be available for missions outside the base. The Pentagon Papers suggest he did see a wider mission, but there is no strong evidence that he did.

ROLLING THUNDER buildup, March

Shortly before Johnson approved the sustained Operation ROLLING THUNDER plan on March 13, the Da Nang security force arrived on March 8. in response to Westmoreland's request of February 22 reflecting a concern with VC forces massing near the Marine air base at Da Nang, 3500 Marine ground troops arrived, the first U.S. large ground combat unit in Vietnam.

President Johnson ordered Chief of Staff of the Army GEN Harold Johnson to assess the situation, already doubting the air offensive before it seriously began. GEN Johnson reported, in Vietnam between March 5 and 12, reported back on 14 March. He was seriously concerned about the situation, and proposed external forces be brought in to free the ARVN for offensive action because "what the situation requires may exceed what the Vietnamese can be expected to do." He proposed a U.S. division be sent preferentially to the Central Highlands (II Vietnamese corps area; Kontum, Pleiku, and Darlac provinces) or to the Bien Hoa/Tan Son Nhut area nearer to Saigon. McNamara, however, did not think such action would make enough ARVN troops available and preferred that a Republic of Korea division be sent rather than U.S. troops. GEN Johnson also suggested a four-division force be raised under the SEATO treaty and used to block infiltration.

GEN Johnson said a decision was needed "now to determine what the Vietnamese should be expected to do for themselves and how much more the U.S. must contribute directly to the security of South Vietnam." Secretary McNamara noted in the margin: "Policy is: anything that will strengthen the position of the GVN will be sent. . ."

Carrot and Stick, April

Johnson's main public announcement at the time, however, was an April 7 speech, in which he offered economic support to North Vietnam, and Southeast Asia in general, if it would stop military action. This offer was quite in keeping with his goals for development, the Great Society, in the United States, and was likely a sincere offer. That he saw such an offer as attractive to the enemy, however, is an indication of his lack of understanding of the opposing ideology.

More elaboration of the proposal was in National Security Action Memorandum 329 This initially classified (but at the lowest level) document, among other things, asked for specific recommendations of a "reviews of the pros and cons" of increasing U.S. aid even before a regional development program started.

As these proposals were made to the North, on 13 April 1965, joint RVN-US discussions agreed that the ARVN force levels were inadequate. The manning level was increased, to increase RVN infantry battalions from 119 (93 infantry, 20 Ranger, and 6 airborne) to 150. The new battalions were generally added to existing regiments, to avoid the need of creating more headquarters units. By the end of 1965, twenty-four were either in the field or in training areas.

In April, Johnson authorized the deployment of an additioal two Marine battalions and up to 20,000 support personnel. Again without public announcement, he changed the rules of engagement to permit the Marines to go beyond static defense, and to start offensive sweeps to find and engage enemy forces.

RVN reverses in May

A VC unit, estimated to be in two-regiment strength, fought the Battle of Song Be, the capital of Phuoc Long province, about 100 miles from Saigon, on 11 May. Song Be was primarily defended by irregular ARVN units, although supported by a Special Forces team and several miscellaneous units. An unprecedented amount of air support, including the first use of a company-sized armed helicopter unit, allowed a successful defense. Higher command, however, was concern that this large a VC unit could take an initiative.

Much farther in the north, later in the month, they ambushed an ARVN force in the north, near Quang Ngai, badly hurting ARVN relief troops and leaving two battalions,

Further ARVN deterioration, June

The impression was confirmed during the battle of Dong Xoai in mid-June. In a textbook display of tactical ineptitude, battalions of ARVN's finest reserves were frittered away piecemeal during the fighting. The violence of the action at Dong Xoai and the level of RVNAF casualties during the second week of June 1965 were both unprecedented.

McNamara proposes escalation, July

In July 1965, McNamara sent Johnson a set of notes proposing escalation of what he saw as a deteriorating situation in South Vietnam. "The situation in SVN is worse than a year ago (when it was worse than a year before that). After a few months of stalemate, the tempo of the war has quickened. . . . The central highlands could well be lost to the NLF during this monsoon season. Since June 1, the GVN has been forced to abandon six district capitals; only one has been retaken...The odds are less than even that the Ky government will last out the year. Ky is "executive agent" for a directorate of generals."

McNamara saw the correlation of forces between the ARVN and the VC is quite unfavorable. "The Govt-to-VC ratio overall is now only a little better than 3-to-1, and in combat battalions little better than 1.5-to-1." A historical rule of thumb for counterinsurgency has been that a 10 to 1 ratio is desirable, but, like all rules of thumb, it is not applicable to all situations. Even a critic of that generalization, "indeed, that ratio was often cited by critics of the U.S. policy in Vietnam", who cite a number of other revolutionary wars where the insurgency was defeated by less overwhelming ratios (e.g., Eritrea against Ethiopia) or where an acceptable goal was partition (e.g., Second Sudanese Civil War), cite the conventional wisdom as primarily relevant to situations of ideological insurgency against a central government, such as the Communist takeover of Vietnam, where the insurgents want complete victory. The current U.S. Army doctrine on counterinsurgency also recognizes there is no simple ratio, "During previous conflicts, planners assumed that combatants required a 10 or 15 to 1 advantage over insurgents to win. However, no predetermined, fixed ratio of friendly troops to enemy combatants ensures success in COIN...A better force requirement gauge is troop density, the ratio of security forces (including the host nation’s military and police forces as well as foreign counterinsurgents) to inhabitants...Twenty counterinsurgents per 1000 residents is often considered the minimum troop density required for effective COIN operations; however as with any fixed ratio, such calculations remain very dependent upon the situation." None of these sources, however, see a 3:1 to 1.5:1 as favorable.

McNamara also observed that the Administration's approach to air war against the North, Rolling Thunder, had not " produced tangible evidence of willingness on the part of Hanoi to come to the conference table in a reasonable mood. The DRV/VC seem to believe that SVN is on the run and near collapse; they show no signs of settling for less than complete takeover."

Autumn and winter, First Airmobile Battles: Ia Drang and Bong Son

Giap's new plan was to use three regiments, but with a new controlling divisional headquarters, across the neck of SVN, cutting the country in two. The division threatened the Plei Me special forces camp with one regiment, but put a second regiment across the road over which South Vietnamese forces, without helicopters, would have to drive to Plei Me from the larger base in Pleiku. Intelligence identified the presence, but at first not the position, of a third regiment, which could attack Pleiku if the reserve based there went to the assistance of Plei Me.

The PAVN preferred hit-and-run ambushes, or what they called "catch and grab." When their retreat was blocked, their next tactic was called "hugging the belt" the Americans hesitated to use artillery and gunships because of the risk of friendly fire casualties. The surprise attack would give a short window of opportunity before superior American mobility could be brought to bear. Moore's after-action reports suggested that "danger close" air and artillery could be a reasonable calculated risk when used competently.

The South Vietnamese recognized they were stretched too thin, and asked for U.S. help. The U.S. Field Force (corps equivalent) commander for the area, MG Stanley Larsen, told GEN Westmoreland that he thought the 1st Cavalry Division (Airmobile) was ready, and got permission for it to use its mobility to bypass the road ambushes. Since the PAVN along the road had planned to ambush trucks, there was not an issue of not being able to find the relieving troops. Helicopters could be heard, but their landing zones were unpredictable until they actually landed — fake landings were not uncommon. In the Battle of the Ia Drang, the first true airmobile force met PAVN regulars.

It should be noted that the PAVN's practice of listening for helicopters was realized by Harold Moore, promoted to brigade command after leading a battalion in the Ia Drang. In the larger Battle of Bong Son approximately a month later, which extended into 1966, Moore used obvious helicopters to cause the PAVN to retreat onto very reasonable paths to break away from the Americans — but different Americans had silently set ambushes, earlier, across those escape routes.