176. Letter From Acting Secretary of State Ball to Secretary of Defense McNamara1

Dear Bob:

I have given careful consideration to the problem of Viet Cong use of Cambodia to support its forces in South Vietnam and, in particular, the Joint Chiefs of Staff views on future U.S. actions regarding Cambodia outlined in your letter of December 29.2 I agree with your conclusion that, unless there is a sudden and significant increase in the use of Cambodian territory by the PAVN/Viet Cong or in logistical support obtained in Cambodia, a gradual and cautious response by the U.S. Government and by certain other friendly governments is appropriate and desirable.

The following are my thoughts on the Courses of Action proposed by the Joint Chiefs and commented upon in your letter:

Course of Action A—The need to expand and intensify the overall intelligence collection program for Cambodia is amply demonstrated by the paucity of hard evidence on the extent and significance of PAVN/Viet Cong use of Cambodian territory and by the differences in interpretation of available information within the intelligence community which have arisen in the course of interagency discussions of the Joint Chiefsʼ proposals. I concur in and am forwarding your letter of December 29 to Admiral Raborn,3 requesting that he ask USIB to re-examine all possible assets to determine additional programs which might be developed to enhance our intelligence capability. I note, however, that among the activities which the Joint Chiefs envisage as being included in a stepped-up intelligence collection program are covert ground cross border [Page 384] intelligence incursions by small teams into Cambodian territory. In any proposal for this type of activity, I would wish to make certain that full consideration is given to the political problems it may raise, particularly should there be any question of the use of Vietnamese or “Khmer Serei” Cambodians.

Courses of Action B and C—I recognize the importance of political and psychological pressure on the Cambodian Government to inhibit Viet Cong use of Cambodian territory, including enlisting support in this effort by other friendly governments. We have already undertaken various actions to this effect, most recently in our December 21 press statement,4 and have had recent consultations with Australia, Canada, the United Kingdom, India and France. We will continue to explore ways which can be effective in persuading Sihanouk that Cambodiaʼs best interests lie in preventing, to the best of his ability, Viet Cong use of Cambodian territory. However, as you are no doubt aware, a principal drawback to our efforts in this respect has been the lack of convincing evidence that use of Cambodian territory, in fact, constitutes a really significant factor for PAVN/Viet Cong operations in South Vietnam or that there has been collusion by the Cambodian Government in such use as has taken place. An aspect of this problem is that the Cambodian Government does not have the capability to control its borders with South Vietnam to the extent of preventing any use at all of its territory by the Viet Cong.

Course D through Course I—I agree fully with your views on these proposed courses of action and have no further comment on them at this time.

In conclusion I should like to point out that unsatisfactory as the present situation in Cambodia is from the U.S. point of view, it would be far worse, it seems to me, if Cambodia were pushed into active belligerency against South Vietnam and against U.S. armed forces or if control authority there were to collapse into civil strife and virtual anarchy as a consequence of border incidents and pressures from such elements as the Khmer Serei movement. Should either of these conditions occur, the Viet Cong and North Vietnamese forces would have a far greater opportunity than they now enjoy to use Cambodian territory for base areas, for refuge, for training, for supply and for infiltration of men and supplies into South Vietnam. In our various calculations as to how to deal with our existing difficulties in Cambodia, I believe that these are dangers which we must always keep in mind.

Sincerely yours,

George W. Ball 5
  1. Source: Department of State, Central Files, POL 27 CAMB. Top Secret. Drafted by Ewing and John M. Kane of SEA on January 12.
  2. Document 171.
  3. See footnote 4, Document 171.
  4. See footnote 2, Document 169.
  5. Printed from a copy that indicates Ball signed the original.