113. National Security Decision Memorandum 901


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


  • Instructions for Strategic Arms Limitation Talks at Helsinki (SALT III)

After considering the discussions and recommendations of the Verification Panel, the President has made the following decisions with respect to instructions for the U.S. Delegation for continuing discussions at Helsinki:2

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The principal aim of the U.S. Delegation will be to elicit a detailed Soviet response to the issues contained in the U.S. proposal tabled in Vienna. Accordingly, the Delegation should avoid volunteering any clarifications except for that in paragraph F below.
In the discussion of “accidental and unauthorized launch,” it should be made clear that this general issue is to be treated as part of a general strategic arms limitation agreement. A separate agreement on this issue cannot be considered at this time.
Should the Soviets propose further negotiations on the proposed agreements for exchange of information and notifications concerning accidental and unauthorized launch of nuclear weapons, the Delegation should take the position:
We can agree to an exchange of information on events (as indicated below) when it is judged that such an exchange of information would be useful in reducing the danger of an unintended war between the U.S. and the USSR.
Immediate mutual notification in the event of an unauthorized, accidental, or otherwise unexplained incident involving the detonation or probable detonation of nuclear weapons.
Mutual exchange of information in the event of detection of unidentified objects by missile attack warning systems, or signs of interference.
Advance notification of planned missile launches and mass take-offs of strategic aircraft.
We should make it clear that each Party would decide for itself which particular events would be subject to information exchange with the other Party. The Delegation should also make it clear that operational practices, such as missile submarine patrols and armed bomber flights, are not considered relevant to this topic.
While communication facilities appropriate to the urgency of specific events would be used, the Washington–Moscow direct communications link3 could be improved for use in critical situations as part of the agreement in this general area.

In response to Soviet queries on the constraint on externally observable modifications of silos, the Delegation should amend the U.S. position to delete the phrase “or which is modified in externally observable ways” and add the following provision:

“Any land-based ICBM silo which is modified in a manner which could provide the silo with a capability to launch a modern, large ballistic missile would be counted toward the limit of 250 launchers for [Page 362] such missiles. Any increase in silo diameter or depth, any permanent removal of a silo liner, any replacement of a silo liner or missile canister with a larger liner or canister, or any other change which could provide the silo with the capability to launch a modern, large ballistic missile would require that the silo be counted toward this limit.”

In the process of negotiation, the Delegation should make clear to the Soviets the specific indicators which we would employ in deciding whether or not a silo could be modified. These indicators would include:

Excavation and/or construction at the external wall of the silo.
Installation of a new or modified missile suspension system.
Installation of a new or modified missile mount.
Prolonged construction operation within or about the silo.
Use of heavy construction equipment, such as cranes.
Activities of the types noted above occurring at a number of similar silos.
Testing of a new missile larger than 70 cubic meters.
Appearance at launch sites of ground support equipment or activities capable of supporting a significantly larger missile than heretofore associated with the sites.

Consideration will be given to dropping the limitations on silo liners and missile canisters from the provision and moving them to the list of indicators if deemed important to negotiations.

In response to Soviet queries on our proposal to retain the right to build a radar capability equivalent to the Soviet Hen House system, the Delegation should explain that the criteria for determining equivalency would include numbers, location and orientation of the radars. The Delegation should state that the detailed description within these parameters is a technical matter to be discussed after agreement is reached on the level of ABM defenses. If pressed, the Delegation can explain that the U.S. recognizes the requirement for each side to have a tactical warning system against ballistic missile attacks. Our concern, however, is the potential of such a system for use in an ABM defense. A limited number of sites, at peripheral locations with outward-looking orientation, helps limit the potential for such use. Considering the characteristics of the Hen House system, an illustrative U.S. equivalent system might be 11 or 12 phased-array radars, outward-looking, at seven or eight peripheral sites.
At some appropriate time, the Delegation is authorized to amend the current position to include a prohibition on production of mobile land-based, sea-based, air-based, or space-based ABM systems in addition to the prohibition on deployment and testing of these systems.
With respect to U.S. forward-based systems, the Delegation is instructed to continue to take the position directed by NSDM–69.4
Except where changed by these Instructions, previous Instructions to the Delegation, including the President’s directive of October 31, 1969, entitled, “Avoidance of Leaks on SALT,” are reaffirmed.5
Henry A. Kissinger
  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; SALT. Copies were sent to the Chairman of the Joint Chiefs of Staff and the senior members of the U.S. SALT Delegation.
  2. Round III began on November 3 and ended December 18.
  3. Commonly referred to as the “hot line.”
  4. Document 94.
  5. See footnote 4, Document 40. In an October 28 letter to the President, Smith expressed concern about the effect of public statements on the negotiations: “I believe you know that I have felt at times in the past that our official line has been too optimistic. Optimism not only has raised expectations unduly, but it tends to reduce our bargaining power against an opponent whose public position is, for the most part, silence. […] I am aware of important considerations other than SALT which bear upon the US public stance in the strategic arms context. Such considerations may lead to a different posture from the one I suggest, but I hope any public information decisions will be taken after consideration of the SALT points which I make in this letter.” (National Archives, Nixon Presidential Materials, NSC Files, Box 879, SALT, SALT talks (Helsinki), Vol. XIII, October–December 1970)