Foreign Relations of the United States, 1964–1968, Volume X, National Security Policy

198. Letter From Secretary of State Rusk to Secretary of Defense McNamara¹

Washington, December 18, 1967.

Dear Bob:

Your prompt and responsive reply of December 1² to my letter of November 24³ concerning the DPMs on General Purpose Forces was greatly appreciated. In my earlier letter I said I would defer until later comment on the DPMs dealing with Strategic Forces and NATO. I have now completed my review of these latter memoranda.

I have no specific suggestions for changes in this year’s force decisions. I do have some thoughts on the effect of our foreign relations of projected future trends in our strategic force posture and what we say about this posture. I believe it would be more useful, however, to comment on these in terms of a study which my staff recently completed rather than on the DPMs themselves.

Several months ago I requested an assessment of the foreign policy implications of recent and projected changes in US and Soviet military forces, with particular emphasis on the strategic forces. I enclose a copy of that study.⁴ I would very much appreciate your comments on it.

It is clear that many of the issues raised in this study require further examination. However, I do think the study highlights the importance of what we say about our strategic posture because of the way in which these statements may be interpreted both by the Soviets and our allies. In particular I think we should try to lead discussions away from such oversimplified concepts as “superiority” or “parity.”

I am sure you agree that it is important that we carefully coordinate the statements which we make to Congress on this score as we have done in past years. To this end I have asked Phil Farley to be in touch with your staff on the posture statement and to focus particularly this year on the strategic forces portion of that statement as well as the review of the international situation.

With warm regards,

Sincerely,

Dean Rusk ⁵

Attachment

SUMMARY OF STATE PAPERS ON CHANGING US-SOVIET MILITARY RELATIONSHIPS

The central theme of the studies is that the US Government should take a fresh look at the political and military implications of the growing strategic parity and changing US-Soviet strategic relationships. The State papers suggest that this can be done through: 1) SIG arrangement for contingency planning on where and how the Soviets would be most likely to intervene in local conflicts, and 2) joint State-Defense development of rationale for US strategic forces, focusing on the rhetoric of deterrence and the major asymmetry in US-Soviet strategies and postures between offense and defensive oriented systems.

The substantive points of the studies fall into three categories: 1) strategic nuclear relations, 2) problems created by increased Soviet strategic mobility and 3) NATO.

On strategic nuclear relations, intelligence estimates point to increased Soviet capability to damage the US in a nuclear exchange, and, over the next decade, the expectation that continued Soviet expansion of their strategic forces may lead to their surpassing the US in some categories of strategic strength. While perceptions of these matters are probably more significant than the “actual” balance, these trends, State tentatively concludes, do not now or in the next five years seem to jeopardize the US deterrent. The problems will not likely be deterrence, but a) increased US domestic controversy, b) uncertainties and pressures leading to “worst case” assumptions in budget planning, c) complications on non-proliferation given obvious vulnerability of US to nuclear attack, and d) greater Soviet inclination to intervene in third areas.

It is this last problem coupled with gradually increasing Soviet strategic mobility that may be of more immediate concern. Evidence of extensive worldwide naval activity, expansion and modernization of airlift-sealift capabilities, allowing for distant but limited operations may tempt the USSR to be more responsive to requests from governments and factions for military support.

On the NATO part, the Soviets have maintained superiority in Central Europe and have modernized their forces (including tactical nuclear weapons). But with US realization that we were not far behind conventionally, the consensus is that a Soviet attack on Western Europe is unlikely. The problem, however, is that the over-all US-Soviet strategic relationship may cause our allies to be more deferential to Soviet political pressures, leading to a further European questioning of the reliability of US commitments.

1. Source: Washington National Records Center, OASD/ISA Files: FRC 330 72 A 1499, 320.9 1968 I–36267/67. Top Secret. The letter forms Tab B to a December 29 memorandum from Warnke to McNamara. A Department of State study is Tab C and a summary of the study prepared for Secretary McNamara forms Tab D (see footnote 4 below). Tab A is a proposed letter from Secretary McNamara to Secretary Rusk, dated January 3, 1968, replying to the latter’s December 18 letter.
2. Not found.
3. Document 194.
4. The Department of State staff paper, entitled “A Study of US-Soviet Military Rela-tionships 1957–1976: Foreign Policy Implications,” December 18, included three attachments: “Comparisons and Trends,” “Soviet Appreciation of the Emerging Military Balance,” and “US Strategic Views.” The study and attachments are not printed, but a Defense Department summary of the paper is printed below.
5. Printed from a copy that bears this typed signature.