Foreign Relations of the United States, 1964–1968, Volume XXVII, Mainland Southeast Asia; Regional Affairs

403. Telegram From the Embassy in Thailand to the Department of State¹

Bangkok, August 15, 1968, 1041Z.

18940. Department also pass SecDef for action. Subject: Future of US Military Establishment in Thailand. State for Secretary Bundy.

1. Once hostilities in Vietnam have substantially declined, we assume that (a) a large proportion of US forces now in the region will be needed for commitments elsewhere, in addition to important political and financial reasons for a phasedown, and (b) there will remain serious grounds for concern about renewal by North Vietnam of actions like those which led to our SEA involvement in the first place, including increased threats to Thailand, Laos and/or Cambodia.

2. US interest in deterring (b) indicates the need for retaining a credible force in SEA, whereas (a) will require that the force be carefully tailored, located and politically emplaced so as to meet the new regional environment, which often will be made as difficult by our friends as by our enemies, not to speak of undefinables like Sihanouk.

3. The obvious, political, diplomatic, and financial requirements for a lean post-hostilities US force—lean especially in terms of numbers of US personnel—from the perspective of Thailand argue against US deployment of ground combat forces in garrisons on the SEA mainland, in the post-hostilities period. In the case of Thailand they argue also against continued reliance on ground-force oriented contingency plans, such as OPlan 1–66 of Project 22. While in 1966 it probably seemed logical to plan for four US brigades and supporting forces to occupy Laotian bridgehead towns in the Mekong lowlands, in response to a NVN attack, with the Thai having lesser roles on the flanks, we have a somewhat more sober concept today of what is really involved in engaging North Vietnamese ground forces 300 miles from the nearest seaport, from a base area already affected by the Thai insurgency. We suspect that Thai leaders have also been chastened by their experience with the insurgency in North Thailand, in contemplating the costs of the major Thai movement and there into neighboring Laos called for in Oplan 1–66. While this plan is useful for the present, especially while a shooting war continues in VN, not only as a factor of reassurance to the Thai but as a factor of uncertainty in the schemes of Hanoi, and while we should not sow doubts in Thai minds about OPlan 1–66 until we have something better in hand, we believe our own forward planning should be developing alternative, more realistic ways of reassuring our allies and deterring the Communists in the Thai-Lao area.

4. The US posture in Thailand—post-Vietnam hostilities—should be premised on a Thailand able to carry a major share of the military defense burden itself, given what are the probable threats, with the US helping out in special fields (principally air) where Thai capability is not developed. Given this premise it is essential that US help RTG build up effective defense forces, through MAP materiel assistance and training appropriate to Thai forces, which are geared to likely threats to Thai territory. On this basis the US posture which takes the best account of many conflicting local and regional considerations, as we now see it, is retention of a substantial though reduced US aviation capability on the less-exposed Thai bases, in support of what are likely to be at least sporadic operating requirements in Laos. Surveillance of any settlement in Vietnam, and visible demonstration to Hanoi of US readiness to support Asian resistance to renewed aggression in SEA. Frequent major ground force exercises (probably in rear areas), involving hyper-modern air and naval capability for fast deployment from Pacific bases, would add the necessary ground force substance to our deterrence, while retaining great flexibility for the US in determining how and when any actual US involvement should occur.

5. At present the Thai Government is very prudent about forward deployment of its land forces. Washington is well aware of the limitations of the Thai armed forces which prevent the RTG from assuming a major share of any contingency role in Laos in response to an NVN attack. We cannot, of course, say that the RTG would not immediately demand full implementation of OPlan 1–66 if its triggering assumptions were enacted by NVN: What we do observe is that RTG budget priorities, military dispositions and readiness posture are not today aimed in this direction, and the RTG may be amenable to a new approach to contingency planning.

6. All factors considered, therefore, a post-Vietnam posture in Thailand of continued presence of substantial US air assets, backed by occasional demonstrations of fast troop deployment capability, in support of contingency planning which envisages primarily (a) supporting Thai efforts to contain an NVN intrusion into Thailand and (b) US-Thai efforts in support of Laotian contingencies emphasizing material assistance to RLG and clandestine operations would best answer US strategic requirements, following a Vietnam settlement, as we can now foresee them. This does not overlook JUSMAG type activities and maintenance of logistic infrastructure which would continue.

7. New military command arrangements would be desirable to emphasize the factors of strength in this new approach, and to develop RTG support for it, lest it be seen as merely a way-stop in retreating from any commitment to Thai security. In order to represent most effectively the US forces which would be the resident expression of US security support for Thailand and Laos, and the new orientation contingency planning, designation of a USAF General officer as the next COMUSMACTHAI would appear desirable. (Naturally the selectee should have had broad politico-military experience.) I would also raise for consideration the carrying of the proposal one step further, in the interest of rationalizing the US Command structure in Thailand, by according him authority over US Air Forces in the pattern of the US Command in Japan.

8. MACTHAI has had since its inception three US Army Generals at its head, who with their special skills answered many valid needs of the period, including setting up the training of the Thai troop commitment to Vietnam, modernization of the RTA, and development of OPlan 1–66. However, indefinite succession of leadership from a single service is not conducive to development of MACTHAI as a truly Joint Command, which it must be increasingly in the 1969–71 period, and alternation of MACTHAI Command among US services would reinforce this broader view. I do not believe that the RTG would take amiss such a change, particularly, if, as I believe is essential, we had very able, experienced US Army general officer as deputy COMUSMACTHAI to continue MACTHAIʼs efforts to modernize the RTA, in conjunction with the Army Advisory Group, and to assist in the smooth transition of contingency plans.

Unger

1. Source: Department of State, Central Files, DEF 1 ASIA SE-US. Secret; Exdis. Repeated to CINCPAC for Admiral McCain and Vientiane for Ambassador only.