Foreign Relations of the United States, 1964–1968, Volume XI, Arms Control and Disarmament

268. Memorandum From Secretary of Defense Clifford to President Johnson¹

Washington, August 13, 1968.

SUBJECT

• Proposal for Limiting Strategic Offensive and Defensive Systems

I. We have examined the Arms Control Proposal as described in Tab A,² and have found that, on balance, and subject to the assumptions and conditions set forth in Section III below, an agreement based upon it³ would allow the actions necessary to preserve U.S. security. Specifically, we conclude that within the terms of such an agreement we would be able to:

a. maintain the U.S. deterrent posture;

b. leave the Soviet Government and world opinion in no doubt as to the adequacy of the U.S. deterrent posture;

c. be confident within the terms of the agreement that our deterrent posture could not be eroded by the actions of the Soviet Union, or any other nuclear power, alone or in combination;

d. maintain a U.S. capability to limit damage to the United States by Soviet forces if deterrence fails, at least as effective as that which we can expect to obtain in the absence of an agreement; and

e. provide a strategic capability that would prevent nuclear powers other than the Soviet Union from threatening the stability of the agreement.

II. Our conclusions in regard to the agreement are based on an analysis of the next 8-10 years. However, we cannot predict new Soviet weapon systems more than a few years ahead, and, therefore, we must continually have the freedom to reassess and to revise the agreement, or withdraw. We know of no way to determine whether the agreement—if it should remain unchanged—will continue to be in our interest. It is contemplated that we would exercise our right to terminate the agreement if we conclude that our national interest can be better protected in a different way. We must be prepared to withdraw at any time if our security requires us to do so.

We also believe that the agreement proposed may well need modification from time to time if it is to continue to preserve our security. In particular, we are concerned that freezing the location and inhibiting our ability to harden existing land-based silos could over time lead to a situation of instability, in that our land-based missile force might be destroyed in a first strike by the Soviet offensive missile forces; this situation could develop if the Soviets were to exploit their potential for substantially increasing their present advantage in throw weight and installing MIRV’s, both of which are permitted under the agreement.

Over the next few years the proposed agreement cannot lead to major budgetary savings and could even require some increases in spending; over a longer period the savings could be substantial if we were able to forego the new programs that might be rendered unnecessary by Soviet acceptance of the agreement and the Soviets decided unilaterally to forego upgrading systems not limited by the agreement. Of greater importance, we believe that the agreement could lead to greater security for the United States over the next 8-10 years, provided that we take the necessary actions to maintain the effectiveness of our strategic forces and remain in a position to react promptly if the agreement is suddenly terminated.

III. Our conclusion that the agreement would preserve the security of the U.S. is based on the following assumptions and conditions:

a. We must be confident that we possess a means of verifying an adequate degree of compliance with the agreement. Based on both the assessment of the Intelligence Community concerning their capability to verify compliance and the sensitivity of U.S. security to Soviet cheating or abrogation, we believe that national means of verification would enable us to monitor the various specific limitations in the agreement, with varying degrees of effectiveness. We have confidence that we would be able to monitor the agreement in terms of numbers of fixed, land-based offensive and defensive missile system launchers of known characteristics. However, within the fixed offensive systems we have low confidence that we can verify the prohibition against upgrading IR/MRBM launchers to an ICBM capability and defensive missile systems to a BMD capability. We also have low confidence that national means of verification would permit us to monitor the terms of the agreement as they pertain to mobile offensive and defensive systems. We must therefore:

(1) make a concerted effort to secure Soviet consent to some form of inspection involving intrusion into each other’s territory and air space to verify limitations on systems other than those which we have reasonable confidence of verifying through unilateral means alone. Such agreed inspection procedures would increase the confidence of each side in the other side’s compliance with the agreement, as well as the general confidence of allies that the results of the agreement are likely to be beneficial. It would permit a more comprehensive agreement. It also is likely to increase the stability of conditions and relationships;

(2) be prepared to use the necessary information from intelligence sources to call possible violations to the attention of the Soviet Union;

(3) be prepared to withdraw from the agreement, if necessary, justifying our actions by the public disclosure of data from intelligence sources;

(4) be prepared to withdraw from the agreement if the Soviets take steps which erode our ability to monitor their compliance, since our verification capability would be significantly degraded by Soviet efforts at concealment, evasion, or interference.

b. An upper limit on ABM defense should be set at an equivalent number of fixed land-based BMD-capable launchers and associated missiles, including reload missiles. The exact ABM limits would be determined during the course of negotiations with the Soviet Union, based upon an assessment of Soviet ABM-capable launchers and missile levels and our overall security objectives as they relate to other nuclear powers and to all the provisions of the agreement. The number should take cognizance of the need to defend against a threat from the CPR or other nuclear power during the period of the agreement.

c. We must have satisfactory assurances that present and future antiaircraft missile systems are not and will not become BMD systems. We should take the initial position that, unless the Soviets can assure us that SA-5 (Tallinn) is not and will not become a BMD system, it must be included in the Soviet ABM launcher limit. The degree of assurance required will depend on the results of technical study of our ability to detect a Soviet program to upgrade Tallinn to achieve various degrees of BMD potential.

d. [3-½ lines of source text not declassified] We must be assured that the Soviets do not replace existing IR/MRBM missiles unless they can satisfy us that the new missiles do not possess an ICBM capability. We would consider their failure to provide us with adequate assurances, as needed, as constituting grounds justifying our withdrawing from the agreement.

e. The agreement covers only what is prohibited and not what is permitted. Specifically, there will be no prohibition on the development or deployment of aircraft and air defense systems (except to prohibit their acquiring a BMD capability), on civil defense, or ASW, on research and development, or on the qualitative improvement of forces within the constraints specified in the agreement. The development and deployment of improved post-boost vehicles capable of delivering MIRV’s to individual targets or on depressed trajectories would not be prohibited.

f. Our judgment of acceptability is based on examination of the proposal as a whole. We have not considered whether separate parts of it would constitute an acceptable agreement. We would want to examine any proposal which was confined to such separate parts, or which proposed an agreement of wider scope.

g. When and if a proposal is approved for negotiation with the Soviet Union, we would want the opportunity to comment on negotiating strategy and tactics, instructions to the delegation, and on the initial presentation and other statements of the U.S. position.

h. The agreement must be in the form of a treaty to be ratified by both countries.⁴

i. The U.S. must make it clear to the Soviet Union that either party would have the right to withdraw from the agreement unless adequate revisions can be negotiated—and in the absence of such revisions the United States must be prepared to exercise its right of withdrawal from the agreement—under any of the following circumstances:

(1) if the capability of any third country reaches the point where either party to the agreement believes that its security is threatened;

(2) if events lead either party to believe that its deterrent capability is threatened;

(3) if there is evidence of substantial concealment of systems affected by the agreement or evidence of evasion of the terms of the agreement;

(4) if either party takes action which interferes significantly with the other’s verification capability or otherwise adversely affects the capability of the other party to verify compliance with the agreement.

j. A system of unilateral safeguards must be established to insure that the agreement continues to be in our interest and to insure that if the Soviets violate or abrogate the agreement, or we decide for other reasons to withdraw from the agreement, that we are in a position to take the steps necessary to maintain our security.

IV. The Deputy Secretary of Defense and the Secretaries of the Army, Navy, and Air Force concur in this memorandum.

The Chairman, Joint Chiefs of Staff, the Chief of Staff of the Army, and the Chief of Staff of the Air Force concur in full in this memorandum. The Chief of Naval Operations and the Commandant of the Marine Corps concur in the memorandum except that they believe that the proposal should be modified as shown at Tab D. The views of the Joint Chiefs are at Tab B.⁵ The views of the Chairman, Joint Chiefs of Staff on the CNO/CMC position are at Tab C.⁶

Clark M. Clifford

1. Source: Johnson Library, National Security File, Intelligence File, Arms Limitation Talk, Box 11. Top Secret; Sensitive.
2. Not found.
3. The Chief of Naval Operations and the Commandant of the Marine Corps believe that the proposal should be revised as indicated in Tab D. [Footnote in the source text. Tab D is an undated paper, “Modification of the Proposal Proposed by the Chief of Naval Operations and the Commandant of the Marine Corps.”]
4. A handwritten notation in the margin next to this sentence reads: “Sect. Rusk questions this. W[alt].”
5. See footnote 4, Document 267.
6. See footnote 3, Document 267.