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

575. Memorandum for the Files by McCone¹

Washington, June 28, 1960

During my discussion with the President on Monday, June 27, he stated:

a. No moratorium on testing now exists (December 29, 1959, Augusta statement),

b. Why shouldn’t we proceed with unannounced tests.

In discussions with the Joint Committee on June 27, concerning the proposed “Joint Resolution” the following questions were raised:

a. Can the seismic improvement program be carried on with older gun type devices (thereby eliminating the use of the Mark 7),

b. Would gun type devices now in stockpile be used or would modifications be necessary and, if so, would these modifications be construed as “weapon developments.”

With reference to the President’s statements:

a. Technically, no moratorium exists at the present time, for on December 29, 1959, he stated: “…… In the meantime, the voluntary moratorium on testing will expire on December 31. (1959)”

“Although we consider ourselves free to resume nuclear weapons testing, we shall not resume nuclear weapons tests without announcing our intention in advance……..”

I agreed with the President that no moratorium existed based on the December 29 statement but, nevertheless, no testing had taken place and, furthermore, the Eisenhower-Macmillan declaration of March 29, offering to conduct a seismic improvement program extended the moratorium for a period during which a limited treaty would be negotiated and signed and a coordinated seismic program completed.

Therefore, for all practical purposes, a moratorium does exist by directive of the President.

b. With reference to the conducting of nuclear tests for weapons development or seismic improvement in secrecy, my investigation indicates this is possible at the Nevada test site because of the vastness of the installation and the diverse activities taking place there. However, there is a very high probability that the activity would become known to the press and, through them, to the public because of the number of people involved and the familiarity on the part of the press with various activities such as safety precautions, unusual instrumentation, and laboratory technicians all of which is unique to a weapons test undertaking.

Therefore, it can be concluded that one or two tests can be conducted without the fact becoming known, but a series (and a series would be required for meaningful results) would, in all probability, become known to the public.

The President’s position caused me to review requirements for immediate tests. It is indicated that testing should be undertaken promptly on the Minute Man, Polaris and the first step on a small Queen weapon. These tests are justified on the basis of safety and dependability.

With regard to the points of the Joint Committee:

a. The seismic program outlined under project Vela calls for use of both the gun type weapons and the Mark 7. Seismologists and the AEC staff consider these as “proven designs”, however, neither the Mark 7 nor the gun type devices now in stockpile will give the exact yields called for under project Vela. The yields are obtained by increasing or decreasing the special nuclear materials in the “proven devices”.

If the program is restricted to existing devices in the stockpile on the theory that only such devices are acceptable as “proven”, then project Vela must be modified considerably. [text not declassified]

It is debatable whether an increase or decrease of the special nuclear material in a proven device could or should be construed as a “weapon development.”

b. If the program is restricted to gun type devices then project Vela, as now laid out, cannot be accomplished. For yields of [text not declassified] a modified program can be developed.

However, for yields above 25 KT and, more particularly for yields under 1 KT (of which 4 are indicated, ranging from [text not declassified]), we must extrapolate from knowledge gained from the present gun type devices for these particular yields are both above and below yields yet attained by us in devices of this type.

It is quite possible that actual yields so extrapolated would vary from the theoretical yields by as much as 30%, plus or minus, and it is also possible that yields of the lower range [text not declassified] might fail entirely. Such extrapolation might very readily be considered as the development of new and heretofore untried weapons as yield of the magnitude anticipated has not been produced heretofore.

[text not declassified] of the Mark 7 device. These devices would always be used because of the economy of the special nuclear material. However, it is important to note that under an arrangement of where the gun type device would be declassified (even on a limited basis), or the Soviets were permitted visual and manual inspection (as provided in the Joint Resolution), and as a result that completed the weapon development, for the reason mentioned above we could not explain that this is not the case because we had alternate devices which are better and more economical (Mark 7’s in stockpile) and such information is classified as Top Secret, Restricted Data.

John A. McCone

1. Source: Record of McCone’s conversation with Eisenhower on considerations for resumed testing. Top Secret; Restricted Data; Eyes Only. 3 pp. Eisenhower Library, McCone Papers, Sealed File No. 5.