94. National Security Decision Memorandum 691


  • The Members of the National Security Council
  • The Attorney General
  • The Director, Arms Control and Disarmament Agency
  • The Director of Central Intelligence


  • Strategic Arms Limitation Talks

After considering the report of the Delegation on the talks to date and the recommendations of the Verification Panel, I have made the following decisions with respect to the U.S. position in the Strategic Arms Limitation Talks:

It apparently being impossible to reach agreement along the lines of either of the two approaches I authorized in NSDM–51,2 the United States will attempt to reach an initial agreement concentrating on imposing numerical limits on the most important strategic weapons systems, with the collateral constraints necessary to make such limits adequately verifiable.
The U.S. proposal for such an agreement will have the following main elements:
—The aggregate total of ICBM launchers, sea-based ballistic missile launchers and strategic heavy bombers would be limited to an agreed number. We would initially propose 1900 as this number.
—Within this aggregate total, launchers deployed after 1965 with a volume greater than 70 cubic meters would be limited to 250. (A separate limitation of this nature is absolutely essential.)
—Within the aggregate total, ICBM and sea-based ballistic missile launchers would be limited to an agreed number. We would initially propose 1710 as this number.
—Within these numerical limits sea-based ballistic missile launchers, land-based ICBM launchers, and strategic heavy bombers could be substituted for each other on a one-for-one basis.
—To enhance confidence in verification by national means, corollary constraints would be imposed on offensive systems, including a ban on relocation of existing ICBM silos or their modification in externally observable ways and a ban on construction of new silos for IR/MRBMs.
—In addition we would initially propose a ban on land-mobile ICBMs and on other land-mobile ballistic missiles and launchers not externally distinguishable from them and a ban on all new ICBM silos (after a transition period for reaching agreed levels). (In the event the Soviets are unwilling to accept a ban on both land-mobile ICBMs and new ICBM silo construction, one or the other must be banned to avoid creation of substantial verification uncertainties.)
—The substance of the definitions, procedures, and other more detailed corollary constraints and additional limitations in connection with limits on offensive forces, as set out for Option D in the April 9, 1970 Memorandum on “SALT Options” attached to NSDM–51 would apply, in so far as they are consistent with these elements.
—There would be no limitation on substitution of new strategic heavy bomber types nor would there be other qualitative limitations on such bombers or their armaments.
—Either of two alternative provisions, of equal status as United States positions, could be agreed for limitation on deployment of anti-ballistic missile systems:
  • NCA” level. Deployment of ABMs would be limited to a system appropriate for defense of the National Command Authority on each side (Moscow and Washington). One hundred fixed ABM launchers and one hundred deployed ABM interceptors would be permitted each side together with associated radars. The Soviet Union would retain its present Try Add and Dog House type radars and ABM launchers operational and under construction, and could add up to 36 additional launchers with associated Try Add radars around Moscow to serve a total of no more than 100 interceptors. The United States would be allowed to deploy a roughly equivalent system, comprising up to 6 PAR faces at no more than two sites, 4 MSR faces at no more than two sites, and 100 ABM launchers and interceptors. On each side, deployment of ABM acquisition and detection radars (PAR-and Dog House-type) would be limited to an area within 200 kilometers of the center of the capital city, and deployment of ABM launchers, interceptors and engagement radars (Try Add and MSR-type) would be limited to an area within 100 kilometers of the center of the capital city.
  • —“Zero” level. Deployment of ABM launchers and interceptors and radars would be prohibited. Existing ABM launchers and associated radars would be dismantled.
—Under either of these alternative ABM levels limitations would be placed on radars suitable for an ABM role. Soviet Hen House-type radars configured for tracking of ballistic missiles would be limited to those currently operational or under construction. We would inform [Page 312]the Soviets that we regard the continued existence of these radars as tolerable partly in view of their present vulnerability, and that we would consider increased SAM defense of such radars as inconsistent with an agreement. The U.S. would have the right to build additional early warning radars to provide equivalent capability to that provided by the Soviet Hen Houses.
—The provisions of Option D of the Memorandum on “SALT Options” with respect to consultation on future radar needs, upgrading of SAMs to give them ABM capability, ABM R&D, procedures for required destruction, mobile ABMs and definitions would apply.
In such an agreement, there would be no limitations on forward-based aircraft, bombers of less than intercontinental range, submarine-launched cruise missiles, or intermediate or medium range ballistic missiles, except for those limits on IR and MRBMs which are necessary to insure adequate verification of the limits imposed on ICBMs. The Delegation is to take the position that any form of “compensation” for excluding forward based aircraft in the form of permitting the Soviets additional missiles of intercontinental range, sea-based ballistic missiles or strategic heavy bombers is wholly and absolutely unacceptable to the United States. If the Soviets raise the question of an exchange of statements or assurances with respect to systems excluded from an initial agreement, the Delegation is to seek further instructions.
The Verification Panel is to prepare a statement of the detailed provisions of a position embodying the elements outlined in paragraph (2) and (3). In general, the substance of the provisions on definitions, procedures, corollary constraints, space and other launchers, and verification, consultation, and duration, etc. of Option D as set forth in the Memorandum on “SALT Options” should apply to the new position as well, except where inconsistent with the elements outlined in paragraphs (2) and (3). However, they should be revised wherever appropriate to increase precision, specificity and clarity. This detailed statement is to be prepared on an urgent basis and is to be available for my consideration by 7 days after the date of issuance of this Memorandum.
Appropriate consultations with the NATO allies on the new position should be carried out as soon as possible.
Pending receipt of the detailed statement of the new position, the Delegation is authorized to present the main elements, as outlined in paragraphs (2) and (3), to the Soviets. After consultation with Washington, the Delegation may, in making such presentation, use a formal statement or less formal means, and may present all the elements at once or present them in stages, as it deems most advantageous from the negotiating point of view. In making any such presentation, however, and particularly in any presentation of the elements in stages, the Delegation must emphasize that the acceptability to the United States [Page 313]of each individual provision is contingent on agreement on the other elements of the new position, including particularly corollary verification provisions and sub-limitations within the overall aggregate.
The Delegation is to make it clear that the United States continues to support a comprehensive agreement, along the lines of either of the approaches already outlined and that we will seek to have an initial agreement followed by further agreements, including if possible controls on multiple independently targetted re-entry vehicles, major mutual reductions in the principal forms of strategic weapons, and limits on IRBMs, MRBMs and submarine-launched cruise missiles.3

Richard Nixon 4
  1. Source: National Archives, Nixon Presidential Materials, NSC Files, NSC Institutional Files (H-Files), Box H–208, National Security Decision Memoranda, NSDMs 51–100. Top Secret; Nodis. Copies were sent to the Chairman of the Joint Chiefs of Staff and senior members of the U.S. SALT Delegation. Haig initialed the memorandum.
  2. Document 68.
  3. In telegram USDEL SALT 221, July 10, the delegation acknowledged receipt of NSDM 69 and noted the following: “The delegation draws attention to the point that all provisions of the new proposal call for equal or equivalent levels of strategic weapons, with the single exception of modern large missiles. Such a differential would appear to freeze the U.S. into a position of inferiority in this respect. We believe it is important to retain for the U.S. the option to build large missiles up to the same number permitted for the Soviets.” On the telegram, Kissinger wrote: “I agree—Larry [Lynn] please see that this applies.” (National Archives, Nixon Presidential Materials, NSC Files, Box 878, SALT, SALT talks (Vienna), Vol. XI, July 1–19, 1970)
  4. Nixon wrote the date he signed the memorandum, July 4, beneath his signature.