Foreign Relations of the United States, 1961–1963, Volume VII, Arms Control and Disarmament

89. Letter From Secretary of Defense McNamara to President Kennedy⁰

Washington, October 31, 1961.

Dear Mr. President: In our letter to you of September 20, 1961,¹ we outlined the basis for a proposed U.S. nuclear test program. By our letter of October 9, 1961,² we further described the experiments which are urgently required and which can only provide the data needed if they are conducted in the atmosphere. The proposed atmospheric tests are listed in the attached tables and fall into four general categories as follows:³

A. Systems Tests

Operational test firings of selected nuclear weapon systems for demonstration, training and effects.

B. Proof Tests

Proof test and yield verification of stockpile weapons.

C. Development Tests

Weapon development experiments.

D. Effects Tests

Weapon effects tests particularly directed toward study of the ICBM warhead and site vulnerabilities and AICBM effectiveness.

In our letter of October 9, 1961, we requested authority to proceed with planning and preparations for the listed tests. You approved this course of action on October 11.⁴ On October 12, the Joint Chiefs of Staff were directed to proceed with plans and preparations in accordance with your approval.⁵

Preparations for the less complicated tests (those in categories A and B) have now reached a point where test operations could begin November 15. We could complete this portion of our program on an orderly schedule by the end of this calendar year.

Based on surface testing,⁶ at an overseas site, approximately six months will be required to prepare for the first of the vitally needed development and effects tests which are listed under categories C and D. The instrumentation for certain of the effects tests is so complex that approximately twenty-four months will be required to prepare for them.

While the requirements from a weapons development viewpoint for the systems tests and the proof tests are not great, such tests do assist in developing operational doctrine and they do add to our knowledge of weapons performance. (The tests of XW 59, XW 56 X1 and XW 50 X1, which are included in category B, will be the first tests of the warheads for Minuteman, Skybolt, Nike Zeus and Pershing.)

The long range missile systems like Atlas D and Polaris are expected to perform properly, but full scale systems tests would materially contribute to the overall confidence in the systems.

The most important question at the present time is whether resumption of atmospheric tests now, at first comprising those systems and proof tests which are useful but not critical from a technical or military standpoint, would facilitate or inhibit conduct of the vitally required development and effects tests some months later. It may well be easier politically to conduct the whole program if we begin atmospheric testing in the immediate future rather than wait for completion of preparations for the critically needed experiments. If this is not the case, and if it is believed as feasible for the United States to begin atmospheric testing some months after the Soviets have concluded their current test series as to begin during or immediately following a Soviet series, the Department of Defense sees little objection to waiting. To have to delay the tests listed in categories C and D until the next cycle of Soviet tests would be seriously prejudicial to U.S. weapon and weapon system development.

We believe that whether or not category A or B tests are undertaken in the immediate future, we should proceed immediately with the selection and preparation of overseas sites for tests in categories C and D.

Robert S. McNamara⁷

0. Source: Washington National Records Center, RG 330, OSD Files: FRC 65 A 3464, Atomic 400.112 8 Apr 61 (Jan-Nov 61). Top Secret; Restricted Data.
1. Document 74.
2. See footnote 2, Document 82.
3. Four enclosed charts, one for each category described in the letter, are not printed.
4. The President’s Appointment Book shows that he met with McNamara, Rusk, Gilpatric, Lemnitzer, and others from 11 a.m. to 12:25 p.m. on October 11. (Kennedy Library) No memorandum of this meeting has been found. In an October 18 memorandum to Kennedy, Bundy stated that there was “an impression in Defense” that the President had approved the October 9 letter. Bundy thought that “the impression should be corrected unless in fact you do approve it. As far as I know, you have not read the letter yet.” (Ibid., National Security Files, Subjects Series, Nuclear Weapons Testing 10/16-29/61)
5. In a memorandum from McNamara to Lemnitzer. (Ibid., Nuclear Weapons Testing 10/11-15/61) See the Supplement.
6. Within the past few days, consideration has been given to conducting some development tests as completely airborne operations over the open seas. If such tests were to be undertaken, preparations could be completed for them by mid-December. Studies of this possibility are continuing. [Footnote in the source text.]
7. Printed from a copy that indicates McNamara signed the original.