See the latest opinion pieces on our pageIn essence, Jerusalem must take all necessary steps to successfully manage an expectedly unprecedented level of adversarial complexity and weaponization. Israel’s leaders, in this connection, must take proper measures to ensure that any conceivable failures of its national deterrent would not spark biological or nuclear forms of regional conflict. To accomplish this indispensable goal, the IDF, inter alia, must continue to plan carefully around the core understanding that nuclear deterrence and conventional deterrence are inherently interrelated and meaningfully “seamless.”Sometimes, in strategic matters, seeing requires distance. A nuclear war in the Middle East is not beyond possibility. This is a sensible assessment even if Israel were to remain the only nuclear weapons state in the region. How is this possible? A bellum atomicum could come to Israel not only as a “bolt from the blue” enemy nuclear attack (either by a state or by a terrorist group), but also as the result, intended or otherwise, of certain uncontrolled military escalations.Needed prudence in such narratives calls for additional specificity and precision. If particular Arab/Islamic enemy states were to launch conventional attacks upon Israel, Jerusalem could then respond, sooner or later, with calculated and more-or-less calibrated nuclear reprisals. Alternatively, if some of these enemy states were to launch large-scale conventional attacks, Jerusalem’s own still-conventional reprisals could then be met, perhaps even in the not-too-distant future, with enemy nuclear counterstrikes.How should Israel prepare for such perilous contingencies? More than likely, Israel has already rejected any doctrinal plans for fielding a tactical/theater nuclear force, and for assuming any corollary nuclear war fighting postures. It would follow further from any such well-reasoned rejection that Israel should do whatever is needed to maintain a credible conventional deterrent.By definition, such a measured threat option could then function reliably across the entire foreseeable spectrum of non-nuclear threats.Still, any such strategy would need to include an appropriately complementary nuclear deterrent, a distinctly “last resort” option that could display a “counter-value” (counter-city) mission function. Si vis pacem, para bellum atomicum: “If you want peace, prepare for atomic war.”A persuasive Israeli conventional deterrent, at least to the extent that it might prevent a wide range of enemy conventional attacks in the first place, could reduce Israel’s growing risk of escalatory exposure to nuclear war. In the always arcane lexicon of nuclear strategy, a complex language that more-or-less intentionally mirrors the tangled coordinates of atomic war, Israel will need to maintain firm control of “escalation dominance.” Otherwise, the Jewish state could find itself engaged in an elaborate but ultimately lethal pantomime of international bluster and bravado.The reason for Israel’s obligation to control escalatory processes is conspicuous and unassailable. It is that Jerusalem’s main enemies possess something that Israel can plainly never have: Mass.At some point, as nineteenth century Prussian military thinker Carl von Clausewitz asserts in On War: “Mass counts.” Today, this is true even though Israel’s many enemies are in chaotic disarray. Now, amid what Clausewitz had famously called “friction” and the “fog of war,” it could become harder for Israel to determine real and pertinent differences between its allies, and its adversaries.As an example, Jordan could soon become vulnerable to advancing IS forces.Acknowledging this new vulnerability, an ironic question will come immediately to mind: Should Israel support the Jordanian monarchy in such a fight? And if so, in what specific and safe operational forms? Similarly ironic questions may need to be raised about Egypt, where the return to military dictatorship in the midst of surrounding Islamist chaos could eventually prove both fragile and transient.Should President Abdel Fattah Sisi fail to hold things together, the ultimate victors could be not only the country’s own Muslim Brotherhood, but also, in nearby Gaza, Palestinian Hamas. Seemingly, however, Hamas is already being targeted by Islamic State, a potentially remorseless opposition suggesting, inter alia, that the principal impediment to Palestinian statehood is not really Israel, but another Sunni Arab terrorist organization. Of course, it is not entirely out of the question that IS’s Egyptian offshoot, the so-called “Sinai Province of Islamic State,” could sometime decide to cooperate with Hamas – the Islamic Resistance Movement – rather than plan to it.To further underscore the area’s multiple and cross-cutting axes of conflict, it is now altogether possible that if an IS conquest of Sinai should spread to Gaza, President Sisi might then “invite” the IDF to strike on Egypt’s behalf. Among other concerns, Egypt plainly fears that any prolonged inter-terrorist campaign inside Gaza could lead to a literal breaking down of border fences, and an uncontrolled mass flight of Palestinians into neighboring Sinai.Credo quia absurdum. “I believe because it is absurd.” With such peculiar facts in mind, why should Israel now sustain a conventional deterrent at all? Wouldn’t enemy states, at least those that were consistently rational, steadfastly resist launching any conventional attacks upon Israel, for fear of inciting a nuclear reprisal? Here is a plausible answer: suspecting that Israel would cross the nuclear threshold only in extraordinary circumstances, these national foes could be convinced, rightly or wrongly, that as long as their initial attacks were to remain conventional, Israel’s response would remain reciprocally non-nuclear. By simple extrapolation, this means that the only genuinely effective way for Israel to continually deter large-scale conventional war could be by maintaining visibly capable and secure conventional options.As for Israel’s principal non-state adversaries, including Shi’ite Hezbollah and Sunni IS, their own belligerent calculations would be detached from any assessments of Israeli nuclear capacity and intent. After all, whatever attacks they might sometime decide to consider launching against the Jewish state, there could never be any decipherable nuclear response.Nonetheless, these non-state jihadist foes are now arguably more threatening to Israel than most enemy national armies, including the regular armed forces of Israel’s most traditional enemies – Egypt, Jordan and Syria.Some other noteworthy nuances now warrant mention. Any still-rational Arab/ Islamic enemy states considering firststrike attacks against Israel using chemical and/or biological weapons would likely take Israel’s nuclear deterrent more seriously. But a strong conventional capability would still be needed by Israel to deter or to preempt certain less destructive conventional attacks, strikes that could escalate quickly and unpredictably to assorted forms of unconventional war.If Arab/Islamic enemy states did not perceive any Israeli sense of expanding conventional force weakness, these belligerent countries, now animated by credible expectations of an Israeli unwillingness to escalate to nonconventional weapons, could be more encouraged to attack. The net result here could be: 1) defeat of Israel in a conventional war; 2) defeat of Israel in an unconventional (chemical/biological/ nuclear) war; 3) defeat of Israel in a combined conventional/unconventional war; or 4) defeat of Arab/Islamic enemy states by Israel in an unconventional war.For Israel, even the presumptively “successful” fourth possibility could prove too costly.Perceptions are vitally important in all calculations of nuclear deterrence. By continuing to keep every element of its nuclear armaments and doctrine “opaque,” Israel could unwittingly contribute to the injurious impression among its regional enemies that Jerusalem’s nuclear weapons were unusable. Unconvinced of Israel’s willingness to actually employ its nuclear weapons, these enemies could then decide to accept the cost-effectiveness of striking first.With any such acceptance, Israeli nuclear deterrence will have failed.If enemy states should turn out to be correct in their calculations, Israel could find itself overrun, and thereby rendered subject to potentially existential harms.If they had been incorrect, many states in the region, including even Israel, could eventually suffer the assorted consequences of multiple nuclear weapons detonations. Within the directly affected areas, thermal radiation, nuclear radiation and blast damage would then spawn uniquely high levels of death and devastation.To prevent a nuclear war amid steadily growing regional chaos, especially as Iran will soon be fully nuclear (and the grateful beneficiary of US President Barack Obama’s pretend P5+1 diplomacy), Israel will need suitably complementary conventional and nuclear deterrents. Even now, at the eleventh hour, it will also require a set of residual but still-available preemption options. Under authoritative international law, actually exercising any such last-resort options would not necessarily represent lawlessness or “aggression.”On the contrary, such strikes could readily meet the long-established and recognizable jurisprudential standards for “anticipatory self-defense.”Going forward, Israeli nuclear deterrence – reinforced, of course, by ballistic missile defense – must become an increasingly central part of the Jewish state’s overall survival plan. Fulfilling this requirement should in no way suggest any corresponding violations of international law. After all, every state in world politics has an overriding obligation to survive.International law is not a suicide pact.The author was educated at Princeton (PhD 1971) and is the author of many books and articles dealing with both US and Israeli nuclear strategy. His recent writings on these complex issues have been published in the Harvard National Security Journal (Harvard Law School); Parameters: Journal of the US Army War College; International Journal of Intelligence and Counterintelligence; Israel Journal of Foreign Affairs; The Brown Journal of World Affairs; The Atlantic; US News & World Report; The Jerusalem Post; The Hill; Oxford University Press; and International Security (Harvard). His tenth book, Israel’s Nuclear Strategy: Surviving amid Chaos (Rowman and Littlefield), will be published later this year. He was born in Zürich, Switzerland, at the end of World War II.