27. National Intelligence Estimate1

NIE 100–5–55


The Problem

To estimate the effects of increasing nuclear capabilites on public attitudes and national policies in the Communist and non-Communist world (excluding the US).


That no international agreement is reached to restrict or prohibit the production, testing, or use of nuclear weapons.


The most important effect in non-Communist countries of growing nuclear capabilities is to diminish the willingness of most governments and peoples to incur risks of war. A second effect is to increase public desire for a reduction of international tensions, and for the use of all possible means, even including those which the governments themselves may consider ill-advised, to work towards a settlement with the Communist powers. Finally, there is increased public pressure on governments to find some means of international disarmament, and especially some means of insuring that nuclear weapons will not be used in war. (Para. 18)
Evidence from the USSR indicates that the Soviet rulers are well aware of the nature and the power of nuclear weapons, which had generally been minimized publicly in Stalin’s time. We believe that they are deeply concerned by the implication of these weapons. US nuclear capabilities almost certainly constitute a major deterrent to overt military aggression by the USSR. (Paras. 13–14, 22)
As nuclear capabilities further increase, and the possibilities of mutual devastation grow, the tendencies to caution and compromise presently discernible in non-Communist countries will probably be accentuated. Aversion to risks of war, pressures for disarmament, and fear of general war, will almost certainly be more marked than now. The difficulties of conducting policy against such adversaries as the Communist leaders will probably be increased, and the chances may become greater of a weakening of the non-Communist position by successive concessions. At the same time the Soviet leaders themselves, because of their recognition of the devastating effects of nuclear weapons, will still almost certainly be concerned not to pursue aggressive actions to the point of incurring substantial risk of general war. (Para. 26)
We believe that the allies of the US, and especially the major allies, will continue in the alliance despite the increase of nuclear capabilities, at least as long as general war does not appear imminent. If general war appeared imminent or actually occurred, their policies would depend in large measure on the course of events. Some of the allies might have no choice, and could not remain uninvolved even if they wished to do so. Some might consider the issues at stake insufficiently important to risk general war, and might therefore declare themselves neutral at an early stage of the crisis. Some governments might estimate that full-scale nuclear war between the US and the USSR would end with complete or near complete destruction of the war-making potential of both powers, and therefore that neutrality might be both a safe and a profitable position. If events developed in such a way as to confront governments with a clear and immediate choice between nuclear devastation and neutrality, we believe that practically all would choose neutrality. (Paras. 27, 30)
As its nuclear capabilities grow, the USSR will have a greatly increased capability to inflict destruction, particularly on the US itself. Nevertheless, the Soviet leaders will probably still not be confident that they could attack the US with nuclear weapons without exposing the USSR to an even more devastating counterblow. We believe, therefore, that the USSR will continue to try to avoid substantial risks of general war despite the increase of its nuclear capabilities. However, as these capabilities grow, Soviet leaders may come to estimate that the US, because of fear for itself or for its allies, or because of pressure by its allies, will be increasingly deterred from initiating full-scale nuclear war. They may therefore come to belive that local wars will be less likely than at present to expand into general war, and thus that superior Bloc military capabilities in certain local areas can be exercised without substantial risk of provoking general war. (Para. 31)
[Page 87]

[Here follows the discussion section (paragraphs 6–32) covering the following topics: “Current Opinion Concerning Nuclear Weapons,” “Influence of Nuclear Weapons Capabilities on Current National Policies,” and “Probable Future Developments.”]

  1. Source: Department of State, INRNIE Files. Secret. According to a note on the cover sheet, the CIA and the intelligence organizations of the Departments of State, the Army, the Navy, the Air Force, and the Joint Staff prepared this estimate, which was concurred in by the Intelligence Advisory Committee on June 14. The Assistant to the Director, FBI, abstained since the subject was outside the jurisdiction of the FBI.
  2. These conclusions were read by Allen Dulles to the NSC on July 14. According to the memorandum of discussion, “the only comment was made by the President to the effect that the people of the world are getting thoroughly scared of the implications of nuclear war. They were running for cover as fast they could go.” (Eisenhower Library, Whitman File, NSC Records)