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

271. Special National Intelligence Estimate¹

SNIE 11-12-68

Washington, August 15, 1968.

EMPLACEMENT OF WEAPONS OF MASS DESTRUCTION ON THE SEABED

The Problem

To estimate the capabilities of US intelligence to monitor a ban on the emplacement of weapons of mass destruction on the seabed—defined as the ocean floor outside territorial waters—and to estimate the likelihood of Soviet or third country deployment of such weapons, during the next 10 years or so.

Scope

For the purposes of this estimate, the following types of weapons are assumed to be prohibited:

a. Manned or unmanned installations containing nuclear weapons or missiles, encapsulated nuclear missiles, and nuclear mines, resting on, anchored to, or imbedded in the seabed.

b. Nuclear weapon systems designed to operate primarily on the seabed but having the characteristic of mobility.

While chemical or biological weapons of mass destruction could theoretically be emplaced on the seabed, the problems of their detection and identification would be the same as in the case of nuclear weapons. Likewise, the considerations affecting intent would be virtually the same. Hence in this estimate, only nuclear weapons are specifically discussed.

Mobile strategic offensive and defensive weapon systems of mass destruction whose principal object is to make use of the seas, as opposed to the seabed, are assumed not to be banned and are, therefore, beyond the scope of this estimate. Neither will the temporary anchorage of ships or submarines to the seabed, whether for emergency purposes, for purposes incident to navigation, for purposes of avoiding detection, or for preparations to launch missiles, be considered in this estimate.

Conclusions

A. We believe that neither the USSR nor any other country would, during the period of this estimate, deploy weapons of mass destruction on the seabed in violation of an agreement banning such deployment. If any signatory decided that it could no longer tolerate the restrictions imposed by the agreement, we believe that it would abrogate the agreement openly rather than try secret evasion, probably after making covert preparations for the prohibited emplacement in advance of the announcement.

B. The time required for detection and verification of a violation would vary with the nature, size, and location of the prohibited deployment. It would be difficult for us to identify a seabed weapon system as such prior to deployment. Detection of predeployment activity, however, and of support systems and activities associated with installation, checkout, maintenance, resupply, and command and control, would arouse our suspicions and would probably lead to eventual detection and identification of the prohibited deployment.

C. We believe that deployment under the open ocean would be detected before a large number of missiles became operational. The deployment of a small number might escape detection for some time after they became operational. [2-1/2 lines of source text not declassified]

D. Even after detection of deployment, verification of a violation would probably be a costly and time-consuming process, [1-1/2 lines of source text not declassified].

Discussion

I. General Considerations

1. In assessing our ability to monitor an agreement of the sort being considered here, it must be remembered that we are dealing with the development and deployment of radically new weapon systems, the characteristics of which we can only imagine on the basis of our knowledge of relevant US and Soviet technology. Essentially, we are faced with consideration of two general types of weapon systems. The first would employ a missile deployed on the seabed and launched to a distant target. Such a system would be highly sophisticated and would use new technology and new methods of operation and control. The other type would consist of a nuclear weapon emplaced on the seabed near its intended target to be exploded without ejection from the water, in the nature of a mine. The characteristics of any such systems would be much different from the characteristics of those weapon systems upon which our past monitoring experience is based. In this respect, any judgments which we make with respect to our capability to monitor a seabed weapons agreement must necessarily be tentative.

2. Our regular sources of intelligence information—SIGINT, overhead photography, and human sources—would be a significant part of our detection capabilities [5 lines of source text not declassified].

3. [11 lines of source text not declassified]

[Here follow Part II: “The Likelihood of Seabed Weapons Deployment” and Part III: “The Monitoring System.”]

1. Source: Johnson Library, National Security File, National Intelligence Estimates, Box 4. Top Secret; Limited Distribution.