In the past, Israel’s policy of deliberate ambiguity regarding its nuclear weapons made sense. Today, however, amid the ongoing Gaza War and the constant aggression on the northern front from Hezbollah, this strategy is no longer tenable.
The principal importance of Israeli nuclear doctrine and strategy lies not only in the ways it can animate and optimize the state’s armed forces, but also in the manner in which Jerusalem can transmit warnings to enemy state Iran and its sub-state proxies, Hamas and Hezbollah.
The threats posed by the Shiite militias in Lebanon and Syria are greater than those issuing from Sunni Hamas in Judea/Samaria and Gaza. Though non-nuclear, the potentially overwhelming threat from Hezbollah may need to be countered by a limited nuclear threat directed by Israel toward Iran, Hezbollah’s state mentor.
For Israel, the shift from nuclear ambiguity to disclosure will need to be authoritative, unhesitating and prompt. For Israeli deterrence and defense policies to be effective, they have to be recognizable as such by Iran and its jihadist terrorist surrogates.
Clarifying nuclear deterrence options
Israel’s nuclear doctrine should be oriented to deterrence ex ante, not revenge ex post. Nuclear weapons can succeed only by calculated postures of strategic non-use. Once these weapons have been used in battle, their critical mission will have failed.
Israel’s nuclear deterrence posture could have counter-terrorism benefits, but only with regard to Iran directly. Conversely, by allowing itself to be weakened by Iran-backed terrorists (Sunni or Shia), Israel exacerbates its vulnerabilities to the Islamic Republic.
While the original Cold War is over, “Cold War II” is well underway between the US, Russia, and (this time around) China and North Korea. If Iran is allowed to go nuclear, Israel’s deterrence relationship with Iran would not be comparable to what once obtained between the US and the USSR. In such circumstances, the continuance of Israeli nuclear ambiguity could cause a nuclear Iran to either underestimate or overestimate Israel’s nuclear retaliatory capacity. Either error could lead to catastrophe.
Exploring conceptual nuances
Uncertainty about Israel’s nuclear strategy could lead not only Iran but other enemy states to dangerous misunderstandings. For example, Israel’s willingness to make good on a threatened nuclear retaliation could be taken as inversely related to the weapon’s destructiveness. In other words, if Israel’s nuclear weapons are thought to be too destructive to use, they might not deter.
The Israeli posture of deliberate nuclear ambiguity could cause Iran to overestimate the first-strike vulnerabilities of Israel’s nuclear forces. Israeli doctrinal opacity could wrongly be interpreted as suggesting porous ballistic missile defenses. Though this conclusion by Iran would seem preposterous after Israel’s extraordinary recent success (April 2024) at active defense, anything less than a 100% probability of interception could be inadequate vis-à-vis Iranian nuclear attacks.
To deter an enemy state attack or post-preemption retaliation against Israel, Jerusalem should strive to prevent a rational state aggressor, via threats of unacceptably damaging retaliation or counter-retaliation, from striking first. Israel’s national security should aim to convince a presumptively rational Iranian attacker (irrational state enemies require a different calculation) that the costs of any attack on Israel would exceed the benefits. Assuming Iran values national self-preservation more highly than anything else and would always choose rationally, it would refrain from launching an attack on an Israel that it believes is willing and able to deliver unacceptably damaging reprisals. This applies whether Iran is nuclear or not.
Capability and willingness
In terms of capability, two components require assessment: payload and delivery system. It should be communicated to Iran that Israel’s firepower and means of delivering it are capable of inflicting unacceptable levels of harm. Israel’s retaliatory or counter-retaliatory forces should appear invulnerable to Iranian first strikes and sufficiently elusive to penetrate Iran’s defenses.
As to willingness, continued ambiguity over Israel’s nuclear posture could create the impression of a state unwilling to retaliate. A movement toward a selective level of nuclear disclosure could heighten the impression that Israel is willing to follow through on its nuclear threats.
What if Iran becomes nuclear? To be deterred, it would need to believe that a critical number of Israel’s retaliatory forces could survive an Iranian first strike and that these forces cannot be prevented from hitting high-value targets in Iran.
The operational benefits of selective nuclear disclosure would accrue from deliberate flows of information concerning Israeli weapons dispersion, multiplication or hardening of nuclear weapon systems, and other technical weapon features. The careful release of information could remove any Iranian doubts about Israel’s nuclear force capabilities and intentions. If left unchallenged, such doubts could undermine Israeli nuclear deterrence against either a pre-nuclear or nuclear Iran.
Israel and limited nuclear war
Inter-state belligerency has two principal variants: asymmetrical nuclear warfare (i.e., a situation in which only Israel is nuclear); and symmetrical nuclear warfare (in which both Israel and Iran are nuclear but where either one side, likely Israel, is more powerful or one or both sides opt for nuclear war limitations).
In the first case, Israel should focus on Iranian threats that are non-nuclear but unconventional. Most obvious would be credible threats of biological warfare, biological terrorism and/or electromagnet pulse (EMP) attack. Also included in the category of Iranian non-nuclear threats would be massive conventional missile attacks launched by proxies like Hezbollah.
While non-nuclear, biological attacks could still produce near-existential outcomes for Israel, an EMP attack, even if severely disruptive, would not likely qualify unto itself as a rationale for an “ordinary” Israeli nuclear reprisal. But Israel could use limited nuclear war ordnance and strategy to render such a reprisal believable and cost-effective.
While Israeli policies of limited nuclear reprisal for biological terror attacks could have some deterrent effectiveness against Iran, such policies might not deter proxy terror groups that function without clear state sponsorship. In these cases, Israel would have to compensate for the lack of suitable targets for calibrated nuclear targeting by falling back on more usual counter-terrorist methods. This could be required even if the terror group has autonomous nuclear capabilities. As to threats issuing from terror groups with state support (e.g., Sunni ISIS-K; Sunni Hamas; Shiite Hezbollah; Shiite Houthis), Israel could direct its nuclear deterrent threats directly toward Iran.
Because jihadist terrorists consider their own death in “holy war” a desirable religious martyrdom, Israeli planners will have to continuously conduct psychological investigations of the enemy. For Israel, a worst-case scenario would see Iranian foreign policy infected with martyrdom thinking.
What about Iranian conventional threats that are neither nuclear nor biological but could still be sufficiently massive to cause Israel existential or near-existential harm? In cases like these (which would likely involve EMP ordnance), Tehran might calculate that Jerusalem would make good on some of its limited nuclear threats – but Israel’s nuclear deterrent threat credibility would be dependent upon a prior doctrinal shift away from deliberate nuclear ambiguity. Without this shift, Iran might not understand that Israel has a sufficiently broad array of nuclear retaliatory responses at its disposal. In the absence of such a confirmable array, Israeli nuclear deterrence could be badly diminished or even fatally degraded.
As a direct consequence of diminished nuclear ambiguity, Jerusalem could signal to Tehran that Israel will cross the nuclear retaliatory threshold to punish all acts of existential or near-existential aggression. Israel’s shift to selective nuclear disclosure would thus bolster Jerusalem’s success in escalation dominance.
Limited nuclear war and international law
No state, including Israel, is under a legal obligation to renounce access to nuclear weapons. In certain circumstances, even the use of nuclear weapons can be lawful (to the extent that such use is consistent with codified expectations of distinction, proportionality, and military necessity).
On July 8, 1996, the International Court of Justice at The Hague handed down an Advisory Opinion on “The Legality of the Threat or Use of Force of Nuclear Weapons.” The final paragraph concludes: “The threat or use of nuclear weapons would generally be contrary to the rules of international law applicable in armed conflict, and in particular the principles and rules of humanitarian law. However, in view of the current state of international law, and of the elements of fact at its disposal, the Court cannot conclude definitively whether the threat or use of nuclear weapons would be lawful or unlawful in an extreme circumstance of self-defense, in which the very survival of the state would be at stake.”
Asymmetrical and symmetrical forms of limited nuclear war
For the immediate future, a limited nuclear war between Israel and Iran would be asymmetrical. At this point, Jerusalem should concern itself less with an Iranian achievement of escalation dominance and more with its own use of limited nuclear war threats designed to keep Iran non-nuclear. Because such use could also be applied to non-nuclear threats from Iran, Jerusalem would need to continuously assess potential nuclear deterrence advantages regarding enemy threats of biological war or terror; EMP attacks on major Israeli cities; and massive conventional attacks.
In a worst-case scenario of asymmetrical nuclear war, Iran could enlist its nuclear North Korean ally to engage Israel in direct nuclear warfare. Though asymmetrical in origin, such a scenario could quickly come to represent an equivalence between the nuclear forces of Israel and North Korea or the de facto nuclear superiority of Pyongyang.
It is possible that a nuclear war involving Israel and Iran could be symmetrical. While it is obviously in Jerusalem’s best interest to prevent such an existential threat at almost any cost, there is no way to ensure such prevention. Israel will need to plan for escalation dominance with a nuclear state adversary (including Iran’s terrorist surrogates), a process that should include selected limited nuclear war options.
Israeli planners will have to establish Iran’s expected nuclear “firebreaks.” As a helpful analogue, they may want to study the differences between the US and Russia regarding “triggers” for crossing from one military threshold to another. Extrapolating from Vladimir Putin’s recent declarations on nuclear warfighting, Moscow still sees tactical or theater nuclear weapons as continuous with conventional, chemical and biological ordnance and not as a critical firebreak between these categories of weaponry and strategic nuclear weapons. The US has always taken the position that a critical firebreak exists between conventional weapons in any form and any level of nuclear ordnance, tactical or theater as well as strategic.
Israel’s objective should be not to build a uniquely advanced weapon, but to figure out how it can best adapt an “ultimate weapon” to deterrence-based strategies of self-preservation. No national challenge could be more important.
{Reposted from BESA}
