Israel’s Posture of Nuclear Ambiguity

When Israel decided in the late 1950s to develop a nuclear option it perceived a permanent existential threat resulting from the basic asymmetries in the various attributes of power between a combined Arab coalition and herself. The nuclear project led to strong American and international objections. President Kennedy who assessed that nuclear proliferation was one of the most threatening international security developments applied considerable pressure on Israel to halt the development of the nuclear option.

Under the strong American pressure and in view of continued international objections, Israel refrained for a long time from actually exercising her nuclear option. Already in 1962, in a high powered meeting in which only the top decision makers participated, Israel decided to indeed continue the nuclear option build up, but to desist from crossing the nuclear threshold (for a discussion of Israel’s nuclear posture see inter–alia, Yair Evron, Israel’s Nuclear Dilemma, London, Routledge Revivals series, 2011). With the coming into force of the Non Proliferation Treaty, the United States continued to demand Israel join the treaty. However, by the late 1960s , in view of the more advanced level of nuclear development  on one hand and the escalation in the conventional arms race following the 1967 War, Israel decided to move ahead and cross the nuclear red line (see Avner Cohen, Israel and the Bomb, New York: Columbia University Press, 1998).

However cognizant of the American objections, Israel declined to actually declare her capability and preferred to develop it in secrecy. Israel and the United States reached an informal understanding that “allowed” Israel to continue developing her nuclear capability provided she would not declare or test it (see Cohen ibid). Thus, the posture of ambiguity had been adopted. The ambiguity was not a calculated strategy, but rather the result of several interfacing factors, especially Israel’s perceived need to have a nuclear capability, as well as the successful development of the nuclear option on the one hand  and American and international constraints on the other.

For quite some time, there has been no doubt internationally that Israel had  acquired a nuclear weapons capability. She is thus considered an “undeclared nuclear power”. Nevertheless, Israel maintains her ambiguous policy. By now, this posture is actually a diplomatic fiction. Nevertheless, diplomatic fictions have their importance. By adhering to her posture of ambiguity Israel has accomplished several objectives. First, as mentioned before, she was able to stem American pressure to disarm her capability. Second, she also calmed to a certain degree international criticism and continued demands that she sign the NPT. Third, she also reduced Arab motivations to “go nuclear”. While Arab leaders most probably know that Israel has an actual nuclear capability, they are reluctant to get involved in a nuclear arms race with Israel. The only state that is relevant in this context has been Egypt. But Egypt decided long ago on the basis of rational calculations not to try to develop a nuclear capability (On Egypt and nuclear weapons see inter alia ; see also James Walsh, “Will Egypt Seek Nuclear Weapons? An Assessment of Motivations, Constraints, Consequences and Policy Options” in William Potter and Gaukhar Mukhatzhanova eds. Forecasting Nuclear Proliferation in the 21st Century, Stanford University Press, 2010).

Instead, she has been concentrating on a diplomatic effort to mobilize international pressure to bring Israel to nuclear disarmament through her joining the NPT. Israel’s posture of ambiguity has “allowed” Egypt and other Arab states to tolerate Israel’s actual capability and thus reduced internal pressure to try and build up their own nuclear capabilities. Indeed, very significantly, the Arab League in its summit meeting of March 2009, decided that if Israel declares her nuclear capability then Arab states would decide to leave the NPT (see Avi Issacharoff, “Arab League: Israel’s nuclear program more worrying than Iran”, Haaretz,17, May 2009; Egyptian delegates in private conversations in various international conferences have emphasized the same opinion and indicated that if Israel adopted an open nuclear posture the domestic pressure inside Egypt to build a nuclear weapons capability would considerably increase).

It is clear now that forgoing the posture of ambiguity would carry serious costs. It would cause harm to American-Israeli relations. It would add another difficulty to the relations between Israel and Egypt. Finally, it would provide Iran with additional ammunition in its quest for nuclearization. Iran continuously argues that the international community is adopting a double standard in its treatment of Iran as compared to Israel. However, were Israel to adopt an explicit nuclear posture, the Iranian claims might gain greater credibility.

Apart from these diplomatic and strategic costs, a change in the posture would adversely affect the cause of international nuclear restraint. Current international efforts led by the United States focus on reducing the saliency of nuclear weapons in international security and in that context enhancing  the viability of the NPT. An Israeli declaration would work in the opposite direction. Undeclared nuclear postures are less provocative than declared ones. This is reflected, for example, in a comparison between the Israeli case on the one hand and the Indian and Pakistani cases on the other. While it was quite well known or at least suspected that both India and Pakistan had small nuclear arsenals before the nuclear tests of 1998, these tests nevertheless changed perceptions of these states’ nuclear status in a meaningful way . There was a general recognition that both countries had crossed an important threshold by testing their undeclared weapons and the blow to the NPT regime was significant. To a certain extent, maintaining the ambiguous posture serves as an arms control measure.


The main mission of the Israeli nuclear capability has been that of “general deterrence” namely deterrence against full fledged wars. The main concern of Ben Gurion who was the main decision maker when the initial nuclear decisions were taken, was the possibility of an existential threat created by the formation of a grand Arab conventional coalition which would overcome the Israeli army. Nuclear weapons were perceived as the ultimate guarantee against it. In fact however, Israel never lost the conventional superiority against her Arab rivals. Israel’s deterrence was maintained primarily by her conventional capability. And when that failed ( in 1973) Israel won by using only her conventional forces. Yet the undeclared nuclear capability served as an extra insurance for Israel against unforeseen adverse developments that might change the balance of power in the region. Currently, because of several developments the balance of conventional military power is tilted even more in favor of Israel.

An undeclared nuclear posture remains a component within the overall capabilities of Israel designed to be part of general deterrence against unforeseen developments. Abandoning the ambiguous posture will not enhance in that sense the deterring effect of the Israeli capability. It will remain in the background .

What if Iran Becomes a Nuclear Power

Were Iran to become a nuclear power the focus of the Israeli nuclear capability would become deterrence of Iran. However, most of the diplomatic costs of a declared posture would remain. But, it could be argued that under such conditions, the posture of ambiguity should be abandoned for strategic reasons and Israel should become a declared  nuclear power. First, in order to emphasize her deterrent capability vis-à-vis Iran. However, in view of the long duration of the existence of the nuclear project and the general international consensus that Israel is a nuclear power including also a second strike capability based on aircraft, ground launched missiles and submarines carrying nuclear cruise missiles, (see on that “Operation Samson: Israel’s Deployment of Nuclear Missiles on Subs from Germany” Der Spiegel, June 4,2012) such a declaration is not really needed. It is clear that the Iranian leadership knows very well that Israel has such a capability.

A second argument in favor of a declared nuclear doctrine is that there is a need for communicating “red lines” for nuclear response. This is needed in order to strengthen deterrence and avoid misunderstandings and unintended escalation. This is specially so in situations of crisis when specific ( or immediate) deterrence is required. An open nuclear strategic doctrine might inject a measure of certainty to deterrence. It might be of particular importance under conditions of escalation between Israel and an adversary allied with Iran. An open doctrine would allow for in-depth analyses and the weighting of various possible scenarios in order to formulate adequate responses for various nuclear challenges. In this context it should be noted that in crisis situations, under conditions of great stress, decision makers tend to rely on “standard operating procedures” that were formulated beforehand in shaping their response in general and particularly in crisis situations.

A possible partial counter argument might be that an important element of the success of deterrence depends on an element of uncertainty. Moreover, decision makers prefer to have a range of options for response and not be tied down to specific ones, and this may not adversely affect the efficacy of deterrence.

A third argument in favor of a declared doctrine is that the Israeli public and indeed decision makers have to “socialize” themselves in nuclear affairs. Thus, for example, the distinctions between “war fighting” and deterrence, or the implications of first strikes and preemption, should be discussed and analyzed. For this there is a need for an open and public discourse among a community of experts. This is required both before an Iranian nuclearization and even more so following it. But as has been mentioned above in this article, such a discussion and consideration can be maintained even under conditions of an official doctrine of ambiguity.

An additional argument in favor of continued ambiguity has to do with American extended deterrence in the Middle East. It is highly likely that following Iranian nuclearization, several Gulf countries would turn to the United States and ask for formal defense guarantees, probably in the form of a defense alliance, and the US would likely extend it.  It would then become probable that Israel would seek a parallel defense alliance with the United States. In view of the very close relations between the two countries, the US is likely to favorably consider the idea. At the same time , bearing in mind the strong American opposition to nuclear proliferation, it would be difficult for the Administration to formalize defense guarantees to Israel if the latter further violates the NPT regime by adopting a declared nuclear posture.


At present there is no convincing argument in favor of Israel changing her policy of nuclear ambiguity. Were Iran to become nuclear, the only strong argument in favor of a declared doctrine has to do with the  injection of a measure of certainty into the balance of mutual nuclear deterrence between Israel and Iran and specially in situations of specific deterrence. While these are important issues, the diplomatic costs could be considerable. What would be the actual Israeli decision remains to be seen.

Yair Evron is professor emeritus in the Department of Political Science, Tel-Aviv University and a senior research associate at the Institute for National Security Studies in Tel-Aviv. He also taught or was research fellow at Sussex, Hebrew, Cornell, Concordia, Harvard, MIT, UCLA , Georgetown and Oxford universities. His most recent publication is “Extended Deterrence in the Middle East”, The Nonproliferation Review, 19:3, November 2012,.

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  • Aaron McKeil

    Thank you for this clear argument. I wish the question of Israel’s nuclear disarmament options was discussed more, since both the issue of Iran’s nuclear legitimacy and Israel’s conventional superiority are discussed.

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