Foreign Relations of the United States, 1969–1976, Volume VIII, Vietnam, January–October 1972

1. Message From the Commander, Military Assistance Command, Vietnam (Abrams) to the Commander in Chief, Pacific (McCain)¹

Saigon, January 20, 1972, 0945Z.

76221. Exclusive for Adm McCain. Deliver during waking hours. References: A. COMUSMACV 041237Z Jan 72. B. COMUSMACV 070812Z Jan 72. C.COMUSMACV 170425Z Jan 72.²

1. (TS) The purpose of this message is to describe in the clearest possible manner the impending enemy offensive against RVN; the impact of ongoing operations on the Commando Hunt interdiction campaign and the additional authorities that will be needed for the conduct of an effective defense in the coming period.

2. (TS) As pointed out in my assessment of the enemy situation submitted in Ref A and B, along with additional intelligence in para 3 below, the enemy is preparing and positioning his forces for a major offensive. It is apparent that the high level decisions and planning for such an effort have already been made by the enemy. Although we cannot be sure at this time of his precise plan of attack it is apparent that he is going to attempt to face us with the most difficult situations of which he is capable.³ There is no doubt that this is to be a major campaign. We estimate that the main effort will be against the B3 front in RVN MR 2 and northern RVN MR 1, but this will be accompanied by a general increase in enemy activity in other areas of RVN. The enemy will use MiG’s, SAM’s and AAA to complicate our operations. We expect his recently intensified MiG activity to continue and to be directed against our air operations. He is expected to position SAM’s and AAA just north of the DMZ and has already moved these weapons into the Laotian panhandle to counter our operations in these areas. These measures will accompany intensive armor and artillery supported ground operations against which we must be able to concentrate U.S. and VNAF air power regardless of the hostile air environment. The enemy will undoubtedly continue operations in Laos or Cambodia against sensitive targets for the purpose of diverting U.S. air power to areas of secondary strategic importance. Difficult strategic decisions will be required on our part to prevent the fragmentation of our air effort. We foresee a hard battle involving sophisticated weaponry and as much ground combat power as the enemy can generate.

3. (S) Since the dispatch of our intelligence assessments of Southeast Asia in References A and B, the enemy has continued to provide clear and positive evidence of his intentions during the next six months.

A. In NVN on 18 December 1971, General Giap, in an official address to high level civilian and military authorities, emphasized that all young men must fight. The theme of Giap’s address stressed “we must fight with determination to win.” The official party organ Nhan Dan, has announced that all youths must go into military service to defend the homeland regardless of past exemptions. Additionally, Hanoi daily newspapers have published photographs of soldiers in combat uniforms and equipment with the caption “Following in the footsteps of their fathers, units on the way to fight in the South.”

B. The southward movement, or preparation for movement, of major tactical units continues. The headquarters of the 320th Division and its three regiments continue their movement toward the VC B–3 front, with the Division headquarters most recently located southeast of Sarvane. The headquarters and one subordinate regiment of the 308th Division have moved over 100 miles south and intelligence indicates that major organic elements of this division are making preparations for deployment. The 304th Division and two of its regiments have relocated significantly south with divisional reconnaisance units reported to be operating west of Khe Sanh. Additonal intelligence reveals that the Division headquarters and regimental elements of the 324B Division are also preparing for deployment. These indicators show a willingness by Hanoi to commit four of the five reserve divisions held in NVN, a commitment which has previously occurred only during Tet 1968 and during Lam Son 719 in March and April 1971. The 271st Independent Regiment, heretofore utilized as a coastal defense and border defense unit in NVN is also moving south. In addition, 122 MM guns and other artillery are enroute to the B–3 front. Intelligence also reveals a very high level of infiltration of personnel and units from NVN into the RVN and Cambodia far in excess of that for a like period last year. Of particular significance is the large number of organized units moving through the infiltration system. The enemy has also extended and improved his air defense capability to the south. Two SA–2 missile firings have occurred from positions in the vicinity of Tchepone, and one from a site 25 nautical miles further south in the panhandle. There has been an increase in the sighting of SAM associated equipment (missiles, launchers, radars, and fire control vans) in the vicinity of the entry gates and along the LOCs in the Laos panhandle. Additionally, intercept of Fan Song radar signals in the vicinity of Vinh Ling just north of the eastern edge of the DMZ indicated a SAM capability in extreme southern NVN. Recently the enemy has increased his conventional anti-aircraft capability in the Laos panhandle to 52 battalions vice 44 held there in the latter part of 1971. Sensor string activations during the past several weeks indicate the enemy is accelerating his logistical campaign in the Lao panhandle. During December 1971, the weekly average of sensor string activations was approximately 3,100. The weekly average for the first two weeks in January 1972 jumped to 5,400, and the third week in January will substantially exceed that average. These most recent developments, General Giap’s statements, unit moves, increased infiltration, build up of SAM and anti-aircraft threat and the continuing increase in truck activity in Laos all indicate the enemy’s intention to make an all-out effort. We believe the enemy will be prepared to mount main force warfare in the B–3 front, northern MR1 and to a lesser extent in MR5 by late January or early February.

4. (TS) The enemy build up has been hurt by the Commando Hunt VII interdiction campaign, but the campaign has been degraded by the diversion of air effort to other missions.

A. Last year our strike sorties in the interdiction campaign in Steel Tiger increased from 6625 in November to 9510 in January. During the same period this year strike sorties have declined in the area from 4967 in Nov 71 to an estimated 4710 sorties in Jan 72. The weight of effort in the interdiction campaign has been affected by the execution of Proud Deep Alpha in Dec 71, the increased strike sorties flown in the Barrel Roll, and the increased air defense sorties required for MiG cap and escort. Although the Barrel Roll area was also active during the 1970/1971 interdiction campaign, the percentage of the total strike and air defense effort devoted to the Barrel Roll area this year has been significantly greater than for the same months last year. For example, in Nov 70, Dec 70, and Jan 71 the percentage of effort devoted to strike and air defense in the Barrel Roll was 11 percent, 9 percent, and 10 percent respectively, as compared with percentages of 17 percent, 17 percent and 32 percent this year.

B. The Arc Light support for the interdiction campaign also reflects the increased emphasis on support for the Barrel Roll. During Nov and Dec 1970, less than one percent of the 1000 monthly sorties went into the Barrel Roll. This compares to 1 and 13 percent respectively during Nov and Dec 71. There were only 96 Arc Light sorties flown in the Barrel Roll during all of 1970, this compares to 114 sorties flown there during Dec 71 alone. During the first 15 days of Jan 1972, 29 percent of all Arc Light strikes went to support the Barrel Roll area. If this rate were continued, nearly 300 of the 1000 available sorties monthly would be flown outside the critical interdiction area. This further reduces the overall interdiction campaign at a time when the total Tacair strike sorties available is significantly less than during the previous campaign.

5. (TS) As noted above the forthcoming battle will probably include MiG and SAM activity in close proximity to the North Vietnam border in the vicinity of the DMZ. Effective protection of our forces will require new operating authorities which must be in hand from the outset of the battle. I therefore request that the following standby authorities be approved now for use as needed throughout the battle. These authorities will be invoked as appropriate when the battle for northern RVN begins.

A. Authority: Fighter aircraft may strike enemy MIG aircraft on the ground at Dong Hoi, Vinh and Quan Lang.

Rationale: MiGs based at these fields pose an unacceptable risk to U.S. and Allied aircraft operating in the DMZ area. MiGs operating from Dong Hoi, the southernmost of the three fields, are only four minutes from northern RVN, even with extensive air defense/MIG cap augmentation, it cannot be assumed that detection and acquisition of NVN aircraft can be achieved in time to prevent MiG attacks against friendly forces. The enemy has demonstrated the ability to use terrain masking and radio silence procedures to deploy undetected into airfields south of 19 degrees north and to launch from these airfields for attack on friendly forces in Laos. In some cases, after-the-fact collateral information has provided the only basis for determination of MIG activity. Tacair strikes near the border, Arc Light, gunships, ABCCC, tankers, and relay aircraft are particularly vulnerable to NVN fighter/interceptor attack. Once MiG’s are positioned at Dong Hoi, Vinh or Quan Lang they must be considered to have entered the battle and must be attacked.

B. Authority: Fighter aircraft, including Iron Hand may strike active GCI radars in NVN below 20 degrees north.

Rationale: For several years NVN has had the resources and ability to integrate the GCI/fighter combination with AAA and SAMs, and thereby establish a highly effective air defense system. During a MiG engagement, GCI radars perform the same function for the MiG as do guidance radars for SAMs. Each time the MiGs have been active, the NVN radar/GCI system begins to radiate just as is the case in preparation for firing surface-to-air missiles. With operative GCI radar the MiG pilots are provided with positive radar control and warning which places them in a vastly superior potion to complete their mission. It is apparent that the aggressive MiG activity is closely associated with the activation of his GCI radars and that the enemy is training intensively toward the end of disrupting operations in Laos and destroying a B–52 or other U.S. aircraft. In addition to the use of GCI radars to control and vector attacking fighters, the enemy is using GCI radars as an integral part of the SA–2 missile fire control system. The SA–2 missiles are aimed and launched using early warning or GCI radar derived azimuth and range information. At a pre-determined time, the Fansong radar is turned on for very short periods to provide terminal guidance information. This tactic effectively negates the protection afforded by our radar homing and warning equipment since there is little time to evade the missile. Whether paired with missiles or MiGs, the EW/GCI radars are being utilized like any other fire control radar; therefore, the authority to strike EW/GCI radars controlling fighter and missile attacks on U.S. and Allied aircraft is necessary to effectively counter the NVN air offense capability in southern Laos and northern RVN.

C. Authority: Fighter aircraft, including Iron Hand, may strike any occupied SAM site and associated equipment in NVN that is located within 19 nautical miles (SAM range) of the PMDL and within 19 nautical miles of the North Vietnam-Laotian border as far north as 19 nautical miles above Mugia Pass.

Rationale: Immediate protective reaction strikes against SAM/AAA and associated equipment as presently authorized leave to the enemy the initiative to contest this critical air space. The principal result to be achieved by the implementation of this proposal is to maintain control of that minimum essential air space required for the conduct of Arc Light and tacair operations in the critical infiltration passes and the anticipated battle zone in northern RVN. We must not allow enemy interference with our use of air power which may be the decisive element in the battle.

D. Authority: Fighter aircraft may strike enemy logistic support facilities below 18 degrees north.

Rationale: The enemy logistics facilities below 18 degrees north will provide direct support to the offensive against RVN. These facilities will be essential to the enemy to sustain his offensive and are considered an integral part of the campaign. Elimination of these facilities will have a direct bearing upon the duration of the battle.

E. Authority: Sensors may be implanted throughout the DMZ. This authority will be executed to the extent required to provide the intelligence deemed necessary for safety of forces.

Rationale: Current authorities permit implanting sensors within the DMZ, south of the PMDL. Expansion of this authority to include the entire DMZ will greatly enhance the ability to monitor resupply and infiltration activity, and permit U.S. and Allied forces south of the DMZ to conduct timely counteractions.

F. Authority: Fixed and rotary wing aircraft may be employed for logistic support, trooplift and medevac in support of RVNAF limited cross-border operations in Laos or the KHR when requirements exceed VNAF capabilities. Rotary wing gunships may be employed when necessary to provide security of these operations.

Rationale: The RVNAF are being encouraged to conduct raids against known or suspected enemy base areas along and near the RVN/Laos and KHR borders. Without the assurance of U.S. backup support, the RVNAF are reluctant to engage in such operations, thereby permitting the enemy to establish and maintain supply and base areas from which to launch offensive operations. This authority will allow us to assist RVNAF during such operations, to insure timely support in emergency situations, and to exploit lucrative targets when discovered.

6. (TS) The seriousness of the developing situation and the need for prior preparation demand the most urgent consideration. The stakes in this battle will be great. If it is skillfully fought by RVN, supported by all available U.S. air, the outcome will be a major defeat for the enemy, leaving him in a weakened condition and gaining decisive time for the consolidation of the Vietnamization effort. When the time comes, it is imperative that the available U.S. air power be focused specifically against the threat to RVN realizing it will mean reduced support for Laos and Cambodia. As it is we are running out of time in which to apply the full weight of air power against the build up. The additional authorities requested in para 5 above are urgently needed, the rate of enemy build-up and our uncertainty as to the exact timing of his offensive pose a most dangerous situation in which the field commander must be accorded maximum flexibility and authority to deal with what will probably be a very rapidly developing enemy threat of major proportions. I view the probable main battle zone as that area north and south of the DMZ in which we can expect to find the main enemy maneuver and combat support forces capable of directly influencing the course of the battle within SVN. I must have the necessary authority to deal with those forces from the outset.

There will not be time for reassessment of the need for additional authorities as in the past. For this reason, I am requesting the removal of those current constraints in our operating authorities which would deny necessary application of force and freedom of action within the battle zone. In the final analysis, when this is all over, specific targets hit in the southern part of North Vietnam will not be a major issue. The issue will be whether Vietnamization has been a success or a failure.

7. Ambassador Bunker has seen this message and concurs.

1. Source: National Archives, RG 330–75–0014, OSD Files, International Security Affairs, Vietnam Task Force, Box 3, File of Meetings, Senior Review Group. Top Secret; Immediate; Exclusive; Specat. Repeated to Moorer. Bunker and Berger in Saigon reviewed the message line by line with Abrams. (Sorley, A Better War, pp. 315–316) During a special briefing in Saigon on the cable and the requested authorities, the following exchange occurred between Abrams and Bunker. Abrams: “As messages go, this is probably the most unequivocal message we’ve ever sent.” Bunker: “I think it’s time to be unequivocal because there’s so much at stake.” Abrams: “I’m in hopes that this will get all the way, or the essence of this will get all the way, to him [the president]. I don’t see how they can afford not to.” Bunker: “I can send in—I can flag it to see that he does.” (Sorley, Vietnam Chronicles, p. 756; “the president” is bracketed in the original.) As it turned out, Bunker had no need to flag the message. When the message arrived, Moorer sent it to Laird and recommended that, “because of the importance of General Abrams’ assessment,” the message should be forwarded to the White House. (CM–1468–72, attached to Moorer Diary, January 20; National Archives, RG 218, Records of the Chairman)
2. COMUSMACV message 1237Z, January 4, and COMUSMACV message 0812Z, January 7, were not found. In COMUSMACV message 0425Z, January 17, Abrams gave his reasons why the enemy would initiate major military action in South Vietnam in a few months. (Ibid., Records of Thomas Moorer, Box 62, COMUSMACV General Service Messages, January 15–31, 1972)
3. Eight days earlier, on January 12, Le Duc Tho in Hanoi had cabled Pham Hung, head of COSVN. In the cable he reminded Pham: “Both we and the enemy are preparing for a ferocious confrontation against one another during the upcoming spring and summer.” Then he added: “Since we have now made our policy decisions and are now beginning to make our deployments to carry them out, it is ever more vital that you maintain a firm tight grasp on the situation [in the South], both the enemy situation and our own situation.” On how to implement the attack plans, Le emphasized, “You must not simply devote all your attention to the activities of our main force units; you must also devote attention to the plan to attack the pacification program and to the plan for political and military struggle in the cities.” (Cable No. 77, Le Duc Tho to Pham Hung, January 12, in Collected Party Documents, vol. 33, 1972, p. 2)