Israeli Nuclear Deterrence Against Broad Spectrum Attacks: Strategic and Legal Considerations

by Louis Rene Beres

“Deterrence is not just a matter of military capabilities. It has a great deal to do with perceptions of credibility.”

– Herman Kahn, Thinking About the Unthinkable in the 1980s (1984)

Abstract: Theoretic assessments of Israel’s nuclear strategy – especially ones concerning a prospective shift from “deliberate nuclear ambiguity” to “selective nuclear disclosure” – generally lack intellectual content. In essence, the most reasonable purpose of any such shift should never be to reveal the obvious – that is, merely that Israel “has the bomb.” This core purpose must always be to uncover what could seemingly best enhance the country’s overall deterrence posture. The threat landscape for Israel has been changing in recent years; to wit, what used to be called the “Arab enemy” has now become less existential. This significant development owes less to the so-called “Abraham Accords” (which “made peace” with only unthreatening Arab states) than to a common Shiite enemy in Iran. Whatever the cause, diminishing Israeli risks of catastrophic war with an Arab state enemy have no readily identifiable correlates with war risks against Iran. In the worst-case scenario, such correlates could exist, but only as a positive or power enhancing (force multiplying) development for Israel.

Starting Point: Defining the Spectrum of Israel’s Deterrent Capacity

From the beginning, Israel’s military defense policies have emphasized technological innovation and purposeful destructiveness. Though such an emphasis has never been incorrect, it has more-or-less ignored certain subtler components of national strategic power. Among other things, these less obvious components include more evident coverage of broad spectrum enemy threats and corollary perceptions of threat credibility.

Today, Israel’s bomb “remains in the basement.” To maximize the efficacy of this still-ambiguous nuclear doctrine, the country’s nuclear weapons and strategy should remain conspicuously relevant deterrents against a fully broad spectrum of possible military harms. In its most refined expression, this doctrine would include nuclear deterrence of certain non-nuclear enemy threats and also be recognizably “seamless.”

Regarding such inherently complex calculations, a great deal would depend upon presumed enemy rationality and on the variable plausibility of issuing nuclear threats against non-nuclear attacks. Meaningfully, this critical dependence would apply both to assorted enemy first strike attacks and to various retaliatory or counter-retaliatory strikes. But how to apply with a view to both strategy and international law?

Pertinent insights must sometimes be counter-intuitive. It is unreasonable to argue that Israel’s nuclear deterrence posture should always parallel or at least closely mirror a particular enemy’s expected level of military destructiveness. A logical place for Jerusalem’s nuclear strategists to begin here would be within the ambit of those enemy threats that are non-nuclear but nonetheless unconventional.

Most obvious in this regard would be credible enemy threats of biological warfare and/or biological terror attack. Though non-nuclear by definition, biological warfare attacks could still produce grievously injurious or near-existential event outcomes for Israel. These outcomes would likely “spill over” more-or-less obviously into United States national security concerns.

What about enemy conventional threats that would involve neither nuclear nor biological harms, but were still potentially massive enough to produce existential or near-existential injury to Israel? In such all-too-credible cases, a prospective conventional aggressor could reasonably calculate that Jerusalem would make good on at least some of its decipherable nuclear threats. Plausibly, Israel’s nuclear deterrent threat credibility could prove dependent upon certain antecedent doctrinal shifts from “deliberate nuclear ambiguity” (the so-called “bomb in the basement“) to “nuclear disclosure.”

Deliberate Nuclear Ambiguity and Non-Rationality

In the absence of any prior shifts away from “deliberate nuclear ambiguity,” a potential aggressor state might not understand or accept that Israel maintains a broad array of differentiable nuclear retaliatory responses. Without such an array, Israeli nuclear deterrence could be more-or-less severely diminished. Additionally, any such diminution could impact certain vital US national security processes and/or objectives.

In part, at least, the nuclear deterrence advantages for Israel of moving from traditional nuclear ambiguity to selective nuclear disclosure would lie in the signal(s) it could “telegraph” to various non-nuclear foes. This signal would warn such adversaries (e.g., Iran) that Jerusalem was not limited to launching retaliations that employ only massive or disproportionate levels of nuclear force. A still-timely Israeli move from nuclear ambiguity to nuclear disclosure – as long as such a doctrinal move were suitably nuanced and plainly incremental – could improve Israel’s prospects for deterring large-scale conventional attacks. It would accomplish this law-maximizing goal by allowing for “tailored” nuclear threats.

After America’s defeat in Afghanistan, a not-yet-nuclear Iran might expect (rightly or wrongly) a militarily less formidable Israel.

Even if Israel’s state enemies were to remain rational, there will still arise certain attendant dangers of an unintentional or inadvertent nuclear war. Such existential dangers could be produced by enemy hacking operations, computer malfunction (an accidental nuclear war) or decision-making miscalculation (whether by the enemy, by Israel itself or by both/all parties.) In the portentous third scenario, variously damaging synergies could surface that would prove difficult or even impossible to halt or reverse.

The Abraham Accords and Emergent Islamist Foes

How, Israeli nuclear strategists should competently inquire, will the Trump-era “Abraham Accords” and America’s loss in Afghanistan affect such dangers? Have these Accords given Israel any tangible reasons for greater security confidence? Could they really enhance “peace” where the included parties were never actual adversaries? And have former President Trump’s agreements actually hardened the Middle East Sunni-Shia dualism, thus making Iran a still-greater existential threat to Israel (a hardening with tangible implications for US defense policy)?

At present, Israel has no regional nuclear adversaries, but the steady approach of an operationally nuclear Iran could encourage rapid nuclearization among such Sunni Arab states as Saudi Arabia or Egypt. Also notable, following the turnover of Afghanistan to Taliban and possibly other Islamist forces, non-Arab Pakistan will likely become a more direct adversary of the United States and Israel. This transformation could emphasize sub-state terror surrogates. Not to be forgotten, the Pakistani jihadist group Lashkar-e-Taiba carried out the large-scale Mumbai, India attack in 2008.

On September 1, 2021, Israel officially moved into the U.S. Central Command’s (CENTCOM) area of responsibility. After taking over from European Command (EUCOM), Jerusalem likely sees its new role as defending U.S. and Israeli interests simultaneously, primarily by countering Iran within CENTCOM’s designated sphere of authority. This countervailing power would be directed at Iran-backed anti-Israel insurgents (especially Hezbollah and Houthi) and at a quickly expanding Iranian nuclearization.

The Question of “Palestine” and “Assured Destruction”

There is more. Salient issues of Israeli nuclear deterrence against non-nuclear threats could be impacted by Palestinian statehood. Once Palestine came into de jure or formal existence as a state, any shift in Israel’s nuclear strategy from deliberate ambiguity to nuclear disclosure could reduce Jerusalem’s incentive to preempt against Iran. But this expectation could make strategic sense only if Israel were first made to believe that its nuclear deterrent threat was now being taken with abundant seriousness by Iran.

Should Israel opt for more open nuclear deterrence based on an “assured destruction” (“counter value”) strategy, Jerusalem would likely choose a small number of relatively inaccurate nuclear weapons. A “counterforce” strategy, on the other hand, would require a larger number of relatively accurate weapons, ordnance that could destroy even the most hardened enemy targets. To a certain presumptive extent, “going for counterforce” could render all Israeli nuclear threats more credible. This conclusion would rest largely on the untested assumption that because the effects of nuclear war-fighting nuclear weapons would be more precise and controlled, they would be more amenable to actual use.

By definition all such nuclear choices will affect international legal standards of permissible weapons and belligerent conduct.

In making its nuclear choices, Israel will have to confront a paradox. Credible nuclear deterrence, essential to Israeli security and survival in a world made more dangerous by the creation of Palestine, would require “usable” nuclear weapons. If, after all, these weapons were patently inappropriate for any reasonable objective, they likely would not deter. At the same time, the more usable such nuclear weapons become in order to enhance nuclear deterrence, the more likely it becomes that they will someday actually be fired.

While this paradox would seem to suggest the rationality of Israel deploying only the least-harmful forms of usable nuclear weapons, the fact that there could likely be no coordinated agreements with enemy states on deployable nuclear weapons points to a different conclusion.

Israel, if confronted by a new state of Palestine, would be well-advised to do everything possible to prevent the appearance of any Arab and/or Iranian nuclear powers, including calculably cost-effective non-nuclear preemptions. Under any and all conditions, Israel would require a believable (hence usable) nuclear deterrent, one that could be employed against non-nuclear threats without igniting “Armageddon” for regional belligerents. In the worst case scenario, Israeli nuclear weapons could also serve damage-limiting military purposes against Iranian weapons (both nuclear and non-nuclear) should nuclear deterrence fail.

Among other serious impacts, the creation of a sovereign Palestine could have dramatic effects on Israel’s forthcoming decisions on “anticipatory self-defense.” Israel’s own presumptive nuclear weapons status and strategy would strongly influence this decision. More precisely, should Jerusalem determine that Israel’s nuclear weapons could support preemption by deterring hostile target states from retaliating, this status might encourage certain Israeli defensive first strikes. If, on the other hand, Jerusalem were to calculate that these target states would be unimpressed by any threats of an Israeli nuclear counter-retaliation, this status would likely not encourage such Israeli defensive attacks.

The prospect of non-rational judgments in the wider Middle East region is always plausible, especially as the influence of Islamist/Jihadist ideology remains determinative among Iranian decisional elites. Still, various dangers of a nuclear conflict will obtain even among fully rational adversaries, dangers of both a deliberate and inadvertent nuclear war. Always, therefore, Israel’s nuclear deterrent must remain oriented toward dominating escalatory processes at multiple and intersecting levels of conventional and unconventional enemy threats.

Whatever happens in direct or indirect consequence of this recommended orientation, impacts will be discernible in certain US defense and foreign policies. This is the case whether or not a “formal” state of war obtains.

Last Words: “I Believe”

In the end, the most persuasive forms of military power on planet earth are not guns, battleships or missiles. They are believable promises of “life everlasting” or immortality. Though “an immortal person is a contradiction in terms,” what is most utterly important to human beings is always obtaining power over death.

Ultimately, Israel’s most compelling forms of strategic influence will derive not from high technology weaponry per se (always a preoccupation in Tel-Aviv), but from the incomparable advantages of intellectual power. These overriding advantages must be explored and compared according to two very specific but overlapping criteria of law and strategy. In certain plausible circumstances, these complex expectations would not be “in synch” with each other, but contradictory. Here, inter alia, underlying “mind over mind” challenges to Israel would become excruciatingly difficult. The United States, after all, incorporates humanitarian international law into its own domestic law.

“Deterrence,” as we learned early on from Herman Kahn’s ‘Thinking About the Unthinkable in the 1980s,’ “is not just a matter of military capabilities.” It is deeply concerned with variously corresponding “perceptions of credibility.” In the matter of employing nuclear deterrent threats against diverse non-nuclear attacks, virtually all pertinent scenarios would be sui generis and starkly complex. Though Kahn supplied earlier generations of nuclear strategists with the analytically useful metaphor of an “escalation ladder,” he also acknowledged that nuclear “players” could sometimes “leapfrog” on this ladder.

What happens then, especially if the out-of-order action is counter-intuitive?

A final observation is needed: Israel’s nuclear posture and strategy will generally affect security policies of the United States. This impact obtains whether Jerusalem’s primary existential disposition is oriented toward nuclear or non-nuclear attack scenarios.

Such scenarios are not necessarily exclusive of one another; conventional conflicts could sometime escalate into unconventional ones. Regarding what can be learned from these disciplined musings, Israeli military planners and decision-makers should soon prepare to support a conspicuously full-spectrum nuclear deterrence option. “Deterrence is not just a matter of military capabilities” we learned from seminal nuclear strategist Herman Kahn. “It has a great deal to do with perceptions of credibility.”

But how should Jerusalem take optimal steps to enhance such indispensable perceptions? Among other things, the correct answer lies in a carefully calculated shift away from deliberate nuclear ambiguity to one of selective nuclear disclosure. The unmistakable point here would not be to convince pertinent adversaries of Israel’s basic nuclear capacities (these are already well recognized), but rather the amenability of these destructive capacities to variously calibrated and nuanced military applications.

In historical terms, there is considerable irony to any such expectation. Soon, it will be important to convince state enemies that Israel’s nuclear military forces are not too destructive or indiscriminately destructive for operational use. Now, in conformance with this seemingly eccentric task, Israel’s intelligence communities will sometimes need to focus less on keeping nuclear secrets (the traditional intelligence branch responsibility in such circumstances) than on supporting nuclear disclosures. Inevitably, providing such support will represent a daunting intellectual task, not just a political one, and will call less for traditional policies of sotto voce communication than for selective national policies of intentional disclosure. Inter alia, in these processes, Israel’s intelligence community goals will extend far beyond any “classical” obligation to safeguard military secrets to a unique responsibility for rendering strategic nuclear policy clarifications.

Fulfilling these complex goals ought never to be considered a matter of ordinary politics or “common sense.” In absolutely all cases, these represent deeply challenging issues of “mind over mind,” theory-based issues that are simultaneously ongoing or foreseeable military operation elsewhere. In this connection, for example, a conflict involving nuclear weapons on the Korean peninsula or in the Ukraine could have very tangible reverberations in Jerusalem and Washington. World politics and world law must always be assessed as a system. Should there ever be any nuclear conflict activity involving North Korea or Ukraine, Israel and the United States would be impacted in several immediately meaningful ways.

In the final analysis, we may add to Herman Kahn’s original 1984 clarification, deterrence is not just a matter of military capabilities or perceptions of credibility. It is also a matter of binding and universal international law. For Israeli nuclear deterrence, strategic and legal considerations are likely overlapping, inter-penetrating and mutually reinforcing. Neither set of concerns should ever be examined in isolation from the other.

Louis Rene Beres was educated at Princeton (Ph.D., 1971), and is Emeritus Professor of International Law at Purdue. His twelfth book, Surviving Amid Chaos: Israel’s Nuclear Strategy, was published in 2016. His other writings have been published in Harvard National Security Journal; Yale Global Online; World Politics (Princeton); Bulletin of the Atomic Scientists; Israel Defense; Parameters: Journal of the US Army War College; Special Warfare; Oxford University Press; The Jerusalem Post; Infinity Journal; BESA Perspectives; US News & World Report; The Hill; and The Atlantic.

His Terrorism and Global Security: The Nuclear Threat (Westview, first edition, 1979) was one of the first scholarly books to deal specifically with nuclear terrorism.

You may find here his latest law review article Israeli Nuclear Deterrence And International Law: Calculating Effects Of Power Politics And Pandemics.

This article was first published in Jurist