Foreign Relations of the United States, 1961–1963, Volumes VII, VIII, IX, Arms Control; National Security Policy; Foreign Economic Policy, Microfiche Supplement

74. Memorandum from Kaysen to President Kennedy, January 5¹

January 5, 1962

1. The problem which confronts you of whether or not to resume testing nuclear weapons in the atmosphere in the near future is in essence one of timing. No one in the government proposes that we unilaterally renounce testing in the atmosphere once and for all. There are those who see a significant political gain in postponing resumption of atmospheric tests for some time, especially if the opportunity so provided is used for positive initiatives in this sphere of arms control and disarmament. The positive argument for the value of such a policy is made by Arthur Schlesinger in his memorandum of 29 December. This memorandum addresses itself to the military disadvantages which must be assessed on the other side of the argument.

2. Harold Brown’s and Jerry Wiesner’s letters to you of 12 and 19 December, respectively, set forth most of the arguments on both sides. I think the most significant part in Brown’s letter lies in his discussion of the individual tests put in the paragraphs at the bottom of page 6 and the top of page 7 which state the framework of military policy within which the assessment of the test series must be made. Brown’s argument was:

“How important these advantages are is a matter of individual judgment. The most likely military situation, in the period at which most of the weapons resulting from these tests would become available, is that the U.S. deterrent posture will be maintained by the variety and numbers of our delivery system. At the same time a first-strike capability which would prevent unacceptable retaliatory damage to the United States will be very difficult no matter what we are willing to spend or do (including atmospheric nuclear testing). This argues that failing to reduce warhead weights by factors of two or even five is not likely to make deterrence infeasible instead of feasible, nor will systems made available by these factors of improvement by themselves make pre-emptive attack feasible instead of infeasible.

“There is, however, a broad spectrum of intermediate situations between pure minimal deterrence and a full first-strike capability, and almost inevitably that is the situation in which the U.S. will find itself. If a war ensues under these conditions, the limitation of U.S. civilian damage resulting from Soviet follow-on attacks or as a result of spill-over from Soviet counter-force attacks will depend to a considerable extent on the details of the survivability, penetrability and deliverability of our own counter-force attack. This statement is not intended to gloss over the fact that in a nuclear war civilian casualties would be enormous in any event and that the societies of the countries involved would be catastrophically and perhaps irreparably damaged. There remains the additional fact that damage will depend in detail how much explosive power is delivered, and at what stage of the conflict, on the enemy’s nuclear delivery capability. These factors depend upon the quality of the nuclear weapons as well as of the delivery systems on each side. This in turn cannot help but affect the calculations made by each side in determining its own estimate of its military strength and its resulting political behavior.”

Within this framework there are two questions to be answered. How important is the extra margin over deterrence which is provided by the capability to strike back at Russian reserve striking power in the event that the Soviet Union initiates an attack upon us? How much contribution will the test series described make to that margin if it is made next spring rather than postponed for a year in the absence of further international agreements or for the duration of any effective agreement?

3. The problem of the margin of strategic striking power beyond what is required for deterrence is one with which you have already wrestled in the decisions on the Defense budget. Although members of your Cabinet and staff differed with regard to this matter, I think certain points on which there was agreement are worth repeating. The Department of Defense argument which justified some striking power beyond that sufficient for what could be called survivable minimum deterrence did not by common agreement indicate just how big this margin ought to be. According to present plans, the size of the margin in the mid-60’s will depend on both the missile buildup and the ability of the bomber force to escape an attack and re-group. It is clear that any technical improvements in warheads and consequent improvement in missiles which testing permits will add something to the probable striking power of a force of any given size. But the significance of this addition must be judged in the context of ambiguity which surrounds any attempt to determine just how big this margin should be.

4. Further, Jerry Wiesner’s paper suggests that some part of the prospective technological losses from the continued postponement of atmospheric testing can be made up by more intensive exploitation of testing possibilities underground and in space. To the extent that this is so the effect of postponement of testing on our military posture is even smaller. We could further reduce these effects, if it were thought necessary, by a bigger force deployment.

5. The relation of atmospheric testing to the development of anti-ICBM systems deserves a further word. The strongest arguments in favor of resumption of testing in the atmosphere are those that relate to what we may learn from effects tests about the related problems of designing AICBM systems and increasing the penetration capabilities of our own missiles against such systems. Here again there is nothing in the proposed Spring tests that is critical to our knowledge or pending decisions in either area. Our present bearish evaluation of the possibilities of Nike-Zeus and similar systems is made without taking into account which might be learned from tests of the effects of nuclear explosions on radar and the like. Thus the new knowledge will show us chiefly how much less good these systems are likely to be. In respect to penetration and reduction of the vulnerability of warheads to nuclear explosions, most of what needs to be learned can be discovered by underground tests.

Finally, there is the argument that atmospheric testing may lead to the discovery of new phenomena relevant to the AICBM problem. This, of course, cannot be denied, but the military exploitation of any such new knowledge, if indeed it accrues, can be achieved only as a result of a long series of tests over a period of years. The possibility of such new knowledge is an important argument against an indefinite unilateral abstention from atmospheric testing. It is not however relevant to the problem of evaluating either the risks of mutual abstention from atmospheric testing or the risks of postponing the resumption of atmospheric tests.

6. By postponing testing in the atmosphere we give up two things of some military value. The first is a reduction of an unknown but not very large amount in the size of the margin which our strategic striking force will offer over the minimum survivable force which provides deterrence. Since we are in some doubt as to how big this margin ought to be, the military significance of a reduction in it is small. The second is a slow-down in the growth of our knowledge on the problems of designing AICBM systems, systems which we expect can only reach a moderate degree of effectiveness in the most favorable circumstances. It is the business of the Department of Defense to concentrate their energies on how our military forces would be used in the event of war. It is your responsibility to look at the broader question of how they can be used to advance our national interests on the whole foreign policy front in peace as well as in war, and thus you should weigh the magnitude of this military loss against the magnitude of the political gains which postponement may offer.

Carl Kaysen

1. Resumption of nuclear weapons testing: weighing the options. Secret. 4 pp. Kennedy Library, National Security Files, Subjects Series, Nuclear Weapons Tests, 12/21/61–1/8/62.