BESA Center Perspectives Paper No. 2,392, June 29, 2026
EXECUTIVE SUMMARY: Any new Israeli government is now legally required to prepare a codified national security strategy within 150 days of its official formation. Though nuclear doctrine and strategy will likely be limited to the highest security-level classifications, nothing could have greater existential impact for Israel. Moreover, at a time when the principal threats to Israel are coming from a still pre-nuclear Iran and certain sub-state proxies, the National Security Council will have to consider wider and more explicit applications of nuclear deterrence. Israel’s decision-makers will need to undertake incremental but prompt shifts from “deliberate nuclear ambiguity” to “selective nuclear disclosure.” Otherwise, Jerusalem will have to accept a strategic reality in which Iran and other adversaries continuously threaten Israel with non-nuclear but high-lethality ballistic missiles and/or chemical-biological (CBW) ordnance – an unsustainable reality of interminable war.
Whatever the shape of Israel’s next war, Jerusalem’s presumptive nuclear weapons are essential for the deterrence of nuclear threats. What is less obvious is that they can also be used to deter non-nuclear threats. The most plausible scenario is one in which a single enemy or coalition of enemies wishes to launch large-scale conventional and/or chemical/biological attacks on Israel, whether first-strike or retaliatory.
Israel’s deterrence posture identifies two seemingly distinct modes of strategic dissuasion: conventional and nuclear. In keeping with the intentionally opaque nature of this posture (i.e., “deliberate nuclear ambiguity”), Israel’s nuclear deterrence would not come into play until all forms of non-nuclear deterrence had been exhausted.
Notwithstanding US President Donald Trump’s purported peace agreement with Iran, the Islamic Republic retains both significant ballistic missile capacity and a willingness to launch against Israel. This remains true despite the fact that Israel is the sole nuclear power in the conflict and hence the only state capable of achieving “escalation dominance.” Why is such a counterintuitive scenario in play? The answer lies in Israel’s unmodified deterrence posture of “deliberate nuclear ambiguity.” Because this posture does not allow for situationally calibrated and nuanced nuclear threats, Israel lacks suitably comprehensive deterrence options.
Assuming Iran is rational, its willingness to desist from conducting non-nuclear ballistic missile attacks on Israel will depend on the credibility of Israel’s deterrence posture. But such credibility can no longer be taken for granted if Israel’s “bomb” remains vaguely deployed in Jerusalem’s “basement.”
And what if Iran or another enemy state were presumptively “non-rational?” In that case, Israel would need to assume a more or less continuous plan for purposeful preemption. Whether an enemy state is rational or not, Israel needs a full-spectrum framework for competitive risk-taking that offers seamless retaliatory options.
Israel requires a secure but flexible military deterrent that can escalate in prefigured increments from non-nuclear weapons (including chemical, biological, hypersonic and/or electromagnetic pulse ordnance) to theater and/or strategic nuclear warfare. Supporting such an informed warning would entail a four-part conceptual understanding:
(1) Science-based judgments of probability must be based on the determinable frequency of relevant past events
(2) There has never been a relevant past event; i.e., a nuclear war
(3) The maintenance of compelling conventional deterrence could make it less necessary for Israel to escalate to nuclear threats/nuclear conflict
(4) Aptly measured nuclear threats could enhance the persuasiveness of Israel’s conventional threats
Sometimes, in strategic matters, truth emerges through paradox. Even without an already nuclear adversary in the region, Israel could find itself having to rely on calibrated nuclear deterrence against biological and/or large conventional threats. On several occasions, Vladimir Putin has proclaimed Russia’s right to introduce nuclear weapons into any future conflict concerning Ukraine. Though that theater of warfare is outside the Middle East, the notion of threatening escalation to nuclear weapons in response to sub-nuclear belligerence could be locally relevant.
What about international law? The adequacy of such law in preventing nuclear war in the Middle East will depend on more than formal treaties, customs, or “the general principles of law recognized by civilized nations”. It will also depend on the success or failure of particular country strategies in the region and on the will of adversarial states to maintain shared intellectual understandings.
Realistic threat scenarios should remind Israel of its overriding need for systemic nuclear theory. This reminder should postulate a counter-value targeted nuclear retaliatory force that is (1) secure from enemy first strikes and (2) capable of penetrating the enemy state’s active defenses. Prima facie, such steps should become part of a critical policy shift from “deliberate nuclear ambiguity” to “selective nuclear disclosure.”
How might Israel become actively involved in a nuclear war? Four basic scenarios present themselves: Nuclear Retaliation; Nuclear Counter-Retaliation; Nuclear Preemption; and Nuclear Warfighting. All these scenarios could be impacted by ongoing and potential future conflicts in North Korea/South Korea; Russia/China/Ukraine, or India/Pakistan.
Selectively released Israeli nuclear information could support the perceived utility and security of Israel’s nuclear retaliatory forces. Once suitably disclosed, national nuclear strategy should center on the targeting, hardening, dispersion, multiplication, basing, and yield of all operational ordnance. Under certain easily imagined conditions, the credibility of Israeli strategic deterrence could vary inversely with the perceived destructiveness of its nuclear weapons.
One further observation concerns Israel’s nuclear strategy and American national security. Though analysts generally examine the foreseeable impact of US nuclear guidance upon Israel, it is equally important to consider the impact of Israel’s nuclear strategy on US national security. Though largely unrecognized, there exists a reciprocal connection between these two factors, a sort of continuous policy feedback loop. Going forward, this loop should be examined more as a dynamic relationship than as a static or one-directional connection.
A starting point should be as follows: The suitability and durability of Israel’s nuclear strategy will legally and strategically affect not only the Middle East, but also American national security. To the extent that Israel’s nuclear policies could have spillover effects for the United States, America could become the unintentional beneficiary of Israel’s strategic planning. It follows that if Israel’s nuclear posture should fail to meet America’s most urgent or existential security expectations, the derivative effect on the United States would be correspondingly negative.
In all such matters, history deserves attention. North Korea helped Syria build a nuclear reactor, the same facility that was subsequently destroyed by Israel in Operation Orchard on September 6, 2007. Unlike Israel’s earlier Operation Opera, this preemptive attack, in the Deir ez-Zor region of Syria, was a second expression of the “Begin Doctrine.” It also portended, because of its North Korea connection, a much wider global threat to Israel.
Deleterious effects would likely be most dramatic if there were ever to be any direct nuclear exchange between the United States and North Korea. Similar effects in the aftermath of an India-Pakistan nuclear exchange would depend largely on Russian/American/Chinese alignments with Delhi or Islamabad. In both prospective conflict dyads – US-North Korea and India-Pakistan – any tangible expressions of nuclear belligerence could immediately impact Israel’s nuclear strategy and Middle East regional security.
“Just wars,” wrote Hugo Grotius, the unrivaled founder of modern international law, “arise from our love of the innocent”. But a nuclear war can never be truly “just,” and certain earlier legal distinctions (e.g., “just war” vs. “unjust war”) should be conformed to the changing technologies of military destruction. The only sensible adaptation in this regard should be to acknowledge timeless connections between international law and natural law and to oppose retrograde movements by powerful states to undermine such acknowledgments.
A nuclear war could arrive in Israel not only as a “bolt-from-the-blue” enemy nuclear missile attack, but also by intended or unintended escalations. If, for example, an enemy state were to begin hostilities by launching “only” conventional attacks on Israel, Jerusalem could decide to respond – sooner or later, foolishly or wisely – with precisely calculated and correspondingly graduated nuclear reprisals. Alternatively, if these enemy states were to commence conflict by releasing larger-scale conventional or biological attacks upon Israel, Jerusalem’s conventional reprisals could be met, at least in the future, with enemy nuclear counterstrikes.
Israel can most effectively reduce its potential exposure to nuclear warfighting by maintaining a credible conventional deterrent. An Israeli non-nuclear deterrent that is fully persuasive, at least to the extent that it can prevent large-scale conventional or CBW attacks, could lower the country’s overall risk of exposure to unmanageable nuclear escalation. In the specific lexicon of nuclear strategy, Israel could reap multiple security gains by staying in visible control of “escalation dominance”. Any rational state enemy considering attacks against Israel using chemical and/or biological weapons would take Israel’s nuclear deterrent more seriously. This argument also suggests that a strong conventional capability will be needed to deter or preempt large conventional attacks.
Inevitably, in seeking to continually reassess their own military power positions, Israel’s enemies will strive to determine how Jerusalem views its own conventional weapon opportunities and limitations. If these enemies do not perceive any Israeli sense of expanding conventional force weakness and are driven by expectations of Israeli unwillingness to escalate to nonconventional weapons, they could decide rationally to attack first. The net result could include: (1) the defeat of Israel in a conventional war; (2) the defeat of Israel in an unconventional (chemical/biological/nuclear) war; (3) the defeat of Israel in a combined conventional/unconventional war; or (4) the defeat of enemy state(s) by Israel in an unconventional war.
Ironically for Israel, even the “successful” fourth possibility could prove net-negative. This counter-intuitive conclusion should once again bring to mind Israel’s increasingly outdated “bomb in the basement”. The credibility of Israel’s nuclear deterrent always depends in part on the perceived “usability” of its nuclear arsenal. Should Israel’s still-ambiguous nuclear weapons be regarded by prospective attackers as high-yield, indiscriminate, “city-busting” (counter-value) weapons rather than as minimal-yield, “war fighting” (counterforce) ordnance, they might not deter.
Successful Israeli nuclear deterrence could thus vary inversely with perceived destructiveness. This means Israel’s nuclear deterrent will require not only recognizably secure second-strike forces but also weapons that can be used in “real war”. It further suggests that the continued Israeli policy of “deliberate nuclear ambiguity” can encourage erroneous and aggressive calculations by prospective attackers.
On one occasion or another, this out-of-date security policy could fatally undermine Israel’s nuclear deterrent. The supposedly valid counterargument that an Israeli end to “deliberate nuclear ambiguity” would encourage new enemy state nuclearization is based neither on historical evidence nor logical inference. From time immemorial, states have almost always done what they believe will maximize the likelihood of their survival. Rarely, if ever, have states been animated by more general interests of an improved world order.
In matters of Israeli nuclear deterrence, it ought never to be minimized that adversarial perceptions will be determinative. By keeping its nuclear doctrine and tangible capacity in the “basement”, Israel could unintentionally contribute to an impression among enemies that its nuclear weapons are not operationally usable. In such circumstances, state enemies, unconvinced of Israel’s willingness to actually employ its nuclear weapons, might calculate the cost-effectiveness of striking first. Depending on the circumstances, such adversarial acceptance could be either reluctant or enthusiastic but still yield the same negative outcome for Israel.
A nuclear war would not respect political or geographic boundaries. Because of the manner in which nuclear explosions behave in the atmosphere, the altitude reached by the distinctive mushroom-shaped cloud would depend primarily upon the force of the explosion. For yields in the low-kiloton range, this cloud would stay situated in the lower atmosphere. Its effects would be almost entirely “local.” For yields exceeding thirty kilotons, however, parts of the cloud of radioactive debris could penetrate the stratosphere, thereby afflicting both the launching state and noncombatant states as well as the target.
To prevent a regional nuclear war, Israel will need to field a fully dependable nuclear deterrent. However, it cannot rely on this necessary basis of national security doctrine any more than it can depend solely on conventional deterrence. Instead, it must depend on complementary nuclear/conventional forces doctrine, interpenetrating systems of air defense, and the availability of sequential preemption options.
In the volatile Middle East, military deterrence is a “game” that sane national leaders will have to play. For Israel, this must be a game of strategy, not chance. This means a continued willingness to respect the full range of doctrinal complexity and to forge ahead with appropriate and presumptively advantageous security policies. To successfully influence the choices that state adversaries could make vis-à-vis Israel, Jerusalem will need to clarify that its conventional and nuclear deterrence postures are seamlessly interpenetrating and that the nation stands ready to counter enemy attacks at absolutely every level of possible confrontation.
There remain just two final points:
First, whether Israel’s overlapping deterrent processes are geared primarily toward conventional or nuclear threats, their ultimate success will depend on the expected rationality of relevant enemies. In cases where enemy rationality appears implausible, Jerusalem could find itself under pressure to strike preemptively. If Jerusalem’s expected responses were to be judged both rational and law-enforcing, they would need to include a wide-ranging option for “anticipatory self-defense”. For Israel, regional conflict prospects should always be curtailed at the lowest possible levels of controlled engagement. Under no circumstances should Israel feel compelled to preempt against an already nuclear adversary. It is Jerusalem’s overriding security obligation to avoid such circumstances.
Second, even the most meticulous plans for preventing a deliberate nuclear conflict would not remove the danger of an inadvertent or accidental nuclear war. While an accidental nuclear war would necessarily be inadvertent, there are forms of inadvertent nuclear war that would not be caused by mechanical, electrical, or computer error. Such forms of unintentional nuclear conflict could be the unexpected result of misjudgment or miscalculation, whether by error committed by one or both sides to a two-party nuclear crisis escalation or unforeseen “synergies” between these misjudgments/miscalculations.
The only predictable element of a nuclear crisis involving Israel and an enemy state is its unpredictability. More than anything else, this implies an obligation by Jerusalem not only to remain vigilant about enemy capabilities and intentions (both singular and cumulative) but to remain cautious about Israel’s capacity to control adversarial nuclear events.
Even after its 2026 military successes against Iran, Israel is entering a period of protracted uncertainty. A core challenge will be deciphering the best course of action on nuclear matters whenever gainful action requires all parties to cooperate. To ward off existential military harm, including unprecedented forms of surprise attack, Jerusalem will need a coherent strategic deterrent, one that incorporates all conceivable threats within a structured system of calibrated reactions. In different situations, making measured nuclear threats could serve Israel’s deterrence objectives before enemy states “go nuclear” and not “merely” because Israel’s conventional deterrent has failed. Reciprocally, Israel’s conventional deterrence, if suitably fashioned, could lower the threshold for Jerusalem to make rational belligerent use of nuclear ordnance.
The principal lesson of the foregoing assessment can be summarized as follows: Under no circumstances should Israel’s military planners embrace a concept of national security that regards conventional and nuclear deterrence as inherently sequential or mutually exclusive. In Jerusalem, where recent law demands an official national security strategy, there can be no more urgent imperative than to begin to take the “bomb” out of the “basement”. Any such incremental replacement of “deliberate nuclear ambiguity” with “selective nuclear disclosure” should be guided by appropriate strategic theory. Only such science-based guidance can reliably prevent the kind of visceral and ad hoc decision-making now driving United States strategic policy.
One final observation strengthens the argument for an Israeli shift to “selective nuclear disclosure”. Any improved national security strategy should openly clarify that Israel’s layered and highly efficient system of active defenses would never hinder or prevent threatened nuclear retaliations. In an earlier BESA Perspective (Paper No. 249), US Air Force General John T. Chain (ret.) and I made the following statement: “In all complex matters of national nuclear strategy, nuance is key. Israel must make it clear to any would-be nuclear aggressor that Arrow defenses would always operate simultaneously or together with Israeli nuclear retaliations. A prospective enemy aggressor state, it follows, must always be made to understand that Israel’s Arrow deployment would never preclude or render less probable an intolerable Israeli nuclear reprisal.”
Today, our clarification should be extended to actual or prospective aggressor states that could inflict massive non-nuclear harms on Israel.
Prof. Louis René Beres was educated at Princeton (Ph.D., 1971) and is the author of many books and scholarly articles dealing with international law, nuclear strategy, nuclear war, and terrorism. In Israel, Prof. Beres was Chair of Project Daniel (PM Sharon). His 12th and latest book is Surviving Amid Chaos: Israel’s Nuclear Strategy (Rowman & Littlefield, 2016; 2nd ed., 2018).
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