Foreign Relations of the United States, 1958–1960, Volume III, Microfiche Supplement, National Security Policy; Arms Control and Disarmament

488. Letter From McElroy to Eisenhower¹

Washington, August 20, 1959

Dear Mr. President:

The Joint Chiefs of Staff have forwarded to me a memorandum dated August 13, 1959, on the subject of phased approach to agreement for the cessation of nuclear weapons tests. A copy of this memorandum is attached for your information.

In their memorandum the Joint Chiefs of Staff question the capability of a control system with existing techniques to detect and identify underwater nuclear explosions. Mr. Gates has forwarded this memorandum to Under Secretary of State Dillon and requested that an assessment of the technical matters raised by the Joint Chiefs of Staff be made as a matter of urgency by Dr. Kistiakowsky. Mr. Dillon has requested Dr. Kistiakowsky to undertake this study.

While I agree that a study of this problem should be made, I do not agree with the views of the Joint Chiefs of Staff as contained in paragraph 4 c of the attached memorandum. Because of the political and psychological implications incident to underwater testing, I do not feel that the Defense Department should support the views that such tests should be grouped with underground tests in any agreements that we might be a party to.

I am sending a copy of this letter to the Secretary of State and to the Joint Chiefs of Staff for their information.

With great respect, I am

Faithfully yours,

Neil McElroy

Attachment

Memorandum From Twining to McElroy

JCSM–326–59

Washington, August 13, 1959

SUBJECT

• Phased Approach to Agreement for the Cessation of Nuclear Weapons Tests (C)

1. The Joint Chiefs of Staff understand that pursuant to a decision by the President, the United States is preparing to adopt a policy of seeking a phased approach to an international agreement for the controlled suspension of nuclear weapons tests. This approach will exclude from the tests cessation agreement any ban on nuclear weapons tests underground or under the surface of inland waters which do not emit radioactivity in amounts detectable by the agreed control system. Tests underwater in the open sea or waters open to the sea such as the United States has conducted in the past would be prohibited.

2. The decision to withdraw underground nuclear weapons tests from any controlled tests cessation agreement is believed to be based on a searching inquiry into the state of the art of seismology which has cast serious doubts on our ability to detect and identify underground nuclear explosions, particularly in the lower yield ranges. New data has indicated that there are techniques available which will allow concealment of such tests from seismographic detection.

3. A review of the findings of the Berkner Panel on Seismic Improvement and other papers prepared by the panel has not indicated an equal concern for our ability to detect and identify the nuclear characteristics of underwater explosions. The techniques of detection and identification for underwater explosions using seismic signals are similar to those for underground. A brief inquiry in this area has indicated that techniques for concealing underwater explosions are feasible and perhaps more readily implemented than those for concealing underground tests. Since seismic methods play a significant role in underwater detection and identification, any doubts as to the capabilities of seismic systems for underground detection should cast doubts also on the capabilities for underwater detection by these means. Hydroacoustic methods for detection of underwater explosions are available. However, identification of the nuclear origin of an explosion is by collection of a sample of radioactive waste. For underwater explosions this is extremely difficult due to the large expanses of ocean areas even though an approximate location by seismic and hydroacoustic methods is determined.

4. With respect to this new policy, the opinions of the Joint Chiefs of Staff are as follows:

a. The state of our knowledge of underwater detection is such that any assumptions as to our capability to differentiate a nuclear explosion from other artificial seismic disturbances may result in an adverse military security position parallel to that we find ourselves in with regard to underground detection. The Soviets may be able to make underwater tests unknown to us and thus make advances in weapon technology and knowledge of weapons effects which we will deny to ourselves.

b. The United States, because of non availability of suitable deep water lakes and inland seas, might be placed at a disadvantage with respect to the Soviet Union if tests under the surface of inland waters are included in the same category as underground tests.

c. That underwater tests in general should be grouped with underground tests until such time as thorough inquiry into underwater detection techniques has confirmed a high probability of underwater detection and identification even in the event of determined efforts toward concealment.

5. The Joint Chiefs of Staff request that you convey the views expressed in this memorandum, as appropriate, to the President and to the Secretary of State.

For the Joint Chiefs of Staff:

N.F. Twining
Chairman
Joint Chiefs of Staff

1. Source: JCS views on phased approach to agreement for the cessation of nuclear testing, underwater testing. Secret. 3 pp. Eisenhower Library, Whitman File, Administration Series, McElroy, Neil, 1959.