Left to themselves, neither suitably deterred nor adequately disarmed, enemies of Israel could one day bring the Jewish State face-to-face with the measureless torments of Dante's Inferno, "Into the eternal darkness, into fire, into ice." It is essential, therefore, that Israel's strategic planners and political leadership now accelerate their basic obligation to strengthen the country's nuclear security posture, and to take all necessary steps to ensure that any conceivable failure of nuclear deterrence could not ignite a nuclear war. Significantly, any such failure would not necessarily be the result of some conspicuous "bolt-from-the-blue" enemy nuclear attack, but could also represent the unanticipated outcome of aggressive crisis escalations.
Now is the time for a detailed and precise enumeration of relevant scenarios. Accordingly, among the most plausible paths to nuclear warfighting in the Middle East are: (1) enemy nuclear first-strikes against Israel (not a present possibility, unless one were to include non-Arab Pakistan as an authentic enemy); (2) enemy non-nuclear WMD first-strikes against Israel that would elicit an Israeli nuclear reprisal, either promptly, or as an inadvertent consequence of escalation processes; (3) Israeli nuclear preemptions against pertinent hard targets in selected enemy states with manifestly recognizable nuclear assets (also not a present possibility, unless Pakistan were included as an enemy state); (4) Israeli non-nuclear preemptions against relevant hard targets in enemy states with operational nuclear assets that elicit enemy nuclear reprisals, either promptly, or incrementally via escalation (again, excluding Pakistan, not a present possibility); and (5) Israeli non-nuclear preemptions against military targets in enemy states without nuclear assets, that would elicit substantial enemy biological warfare reprisals, and, reciprocally, Israeli nuclear counter-retaliations.
Still, other more-or-less plausible paths to nuclear warfighting in the Middle East include accidental, unintentional, inadvertent, or unauthorized nuclear attacks involving Israel and certain identifiable regional foes. The very last scenario offered here – "unauthorized" enemy nuclear attacks – should bring to Israeli analytic consideration an always-possible Jihadist coup d'état in Islamic Pakistan.
Jerusalem must also bear in mind the potentially dire and starkly unpredictable prospect of a major escalation arising from any specific instance of WMD terrorism against Israel. In this connection, Israeli strategists will not only need to consider their terrorist adversaries as singular or isolated actors, but also as prospective members of possible "hybrid" combinations, ones fashioned with other sub-state terror organizations, and/or with certain likeminded states.
Already, Israel has had to deal with a distinctly unique form of nuclear terrorism in the form of enemy attacks upon its Dimona nuclear reactor. While never given any genuine public attention – most obviously, perhaps, because both attacks were actual operational failures – the significant fact remains that Dimona came under enemy missile or rocket fire in 1991, from Saddam Hussein's Iraq, and again in 2014, from Hamas. It is not at all unreasonable to expect that in the future, a more determined and capable adversary could produce some calculable breach of nuclear reactor containment, and thereby initiate a perilous spiral of potentially lethal escalation.
As long as Israel remains determined to survive at all costs, its leaders must be prepared to identify and catalog all those specific circumstances wherein the country could become enmeshed in an actual nuclear exchange, or in nuclear warfighting. These fearful circumstances will obtain as long as (a) pertinent enemy first-strikes against Israel do not destroy Israel's second-strike nuclear capability; (b) enemy retaliations for an Israeli conventional preemption do not destroy Israel's nuclear counter-retaliatory capability; (c) Israeli preemptive strikes involving nuclear weapons do not destroy enemy second-strike nuclear capabilities (not a present concern); and (d) Israeli retaliations for enemy conventional first-strikes do not destroy enemy nuclear counter-retaliatory capabilities (also, not a plausible concern at present).
From the plainly vital standpoint of Israel's nuclear security requirements, this all means that Jerusalem must now prepare to do absolutely whatever is needed to ensure the likelihood of (a) and (b) above, and also the corollary unlikelihood of (c) and (d).
Among other things, Israel needs its presumptive nuclear weapons to preempt enemy nuclear attacks. This does not mean that Israeli preemptions of such obviously intolerable attacks would necessarily be nuclear themselves – more than likely, they would be entirely non-nuclear – but only that they could conceivably be nuclear. Moreover, both Israeli nuclear and non-nuclear preemptions of unconventional enemy attacks could, at least in principle (and also in the future) produce some form or other of nuclear weapons exchange.
The actual outcome here would depend, in large part, upon the effectiveness and breadth of Israeli targeting, the surviving number of enemy nuclear weapons, and the demonstrated willingness of enemy leaders to risk an Israeli nuclear counter-retaliation. Arguably, especially in reference to a still-nuclearizing Iran, the actual likelihood of some nuclear exchange would be greatest wherever Israel's relevant foe were allowed to continue its overt or covert nuclear weapons development without suffering any preemptive military interference. Still, over time, and the July 2015 Vienna Pact on Iran notwithstanding, a truly nuclear Iran is perhaps already a fait accompli. Israel, therefore, will need to figure on how best to live with a nuclear Iran.
Leaving tactical details aside, this suggests prudent Israeli preparations for long-term nuclear deterrence, buttressed by increasingly advanced forms of cyber-warfare and ballistic missile defense. Always, for Israel, recognizable preparations for strategic dissuasion must be augmented by similarly observable preparations for denial.
For Israel, the sole military alternative at this point, an eleventh-hour defensive first strike against Iranian nuclear assets, would almost certainly carry unacceptable risks, both physical and political. Moreover, at this late operational date, it would prove exceedingly difficult for Jerusalem to make the necessarily supportive jurisprudential argument that its utterly massive preemption was a proper expression of "anticipatory self-defense." All things considered, Israel will have to forego any last-minute preemption against Iran, and rely, however reluctantly, upon some still-promising forms of protracted deterrence and mutual coexistence.
In the final analysis, Israel's most significant risks of a nuclear exchange or nuclear war will arise from certain predictable kinds of crisis escalation. These are "locked-in" competitions wherein Israel's core national obligation to avoid recklessness could be rapidly and irremediably overtaken by the presumed imperatives of "winning" through "escalation dominance."
Louis René Beres is Emeritus Professor of International Law at Purdue. He lectures and publishes widely on matters of Israeli security and nuclear strategy.