5 min readApr 7, 2026 02:06 PM IST First published on: Apr 7, 2026 at 02:06 PM ISTThe killing of Ayatollah Ali Khamenei in the opening phase of the US-Israel war against Iran has generated a striking argument: That his death may have removed not merely a political leader but also a normative brake on Iran’s possible march toward nuclear weapons. Reports indicate that Iranian decision-making has since hardened under intense military pressure and an increasingly securitised internal environment.What gives Khamenei’s death particular doctrinal significance is that he had, over more than two decades, publicly framed weapons of mass destruction — including nuclear and chemical weapons — as contrary to Islam. If that position represented a genuine religious constraint rather than diplomatic rhetoric, his death may have weakened the very restraint that kept Iran a threshold nuclear state. The central question is whether a moral tradition can discipline a state that increasingly experiences its insecurity as existential.AdvertisementClassical Islamic thought does not treat war as an unbounded field of religious violence. It regulates warfare through a moral-legal framework derived from the Qur’an, the practice of the Prophet, and centuries of juristic tradition. The foundational Qur’anic injunction, verse 2:190, both permits fighting and limits it: “Fight in the way of God those who fight you, but do not transgress. Indeed, God does not love transgressors.” War is accepted as a political reality but is not treated as morally autonomous.The duality of permission and restraint thus runs through the Islamic just war tradition. Even a just cause does not license unlimited means. Islamic jurists emphasised proportionality, legitimate authority, and the protection of non-combatants — developing a norm of discrimination that restricted violence to active combatants. It is from this perspective that nuclear weapons become especially difficult to reconcile with Islamic ethics. A weapon whose essence is mass, uncontrolled devastation, sits uneasily with any tradition that treats non-combatant immunity as morally central. The problem is not simply the scale of destruction, but the very structure of the act: The means themselves are transgressive.Khamenei extended this tradition to the nuclear realm, issuing an oral fatwa in October 2003 declaring nuclear weapons forbidden (haram) and repeating this position at the International Atomic Energy Agency in August 2005. Yet the fatwa’s authenticity has always been contested. Critics have argued that no formal written fatwa was ever issued — that what Iran marketed as a binding religious ruling was, in origin, merely the closing paragraph of a 2010 disarmament conference message, later retroactively framed as a fatwa by Iranian diplomats. Khamenei’s pronouncements were also inconsistent: At times, he forbade development, stockpiling, and use; at other times, he appeared to permit development and stockpiling while forbidding use.AdvertisementAlso Read | The new Dhaka is not interested in performative anti-India posturingNone of this entirely strips the fatwa of significance. In political systems where legitimacy is partly theological, a public prohibition from the supreme jurist, however ambiguous in legal form, raises the cost of reversal. Such declarations make it politically expensive to overturn the publicly stated position even if they do not constitute formally binding juridical rulings. The fatwa functioned less as an iron constraint than as a reputational anchor.On March 9, the Assembly of Experts named Mojtaba Khamenei, the 56-year-old son of the assassinated supreme leader, as Iran’s third supreme leader, under wartime duress and with strong backing from the Islamic Revolutionary Guard Corps. Whether he will inherit his father’s doctrinal commitments is far from clear. Mojtaba is not known as a jurist of comparable standing; his authority derives from revolutionary and security credentials rather than theological learning — a fact noted critically within Iran’s clerical establishment, which has historically resisted father-to-son succession as uncomfortably monarchical.Khamenei’s nuclear prohibition carried weight precisely because it came from the state’s highest religious authority. Mojtaba’s contested standing means any comparable prohibition would carry less doctrinal force — while any tacit relaxation would accelerate the erosion of the barrier his father maintained. The IRGC commanders who manoeuvred his appointment have long been among those pressing for a reassessment of Iran’s nuclear posture.you may likeThis leads to the final and perhaps hardest question: Would Iran, if acting as a pure realist state, pursue nuclear weapons regardless of the Islamic just war tradition? The realist answer is straightforward: States seek survival, and a bomb promises regime survival, deterrence, and insulation from future attack. And yet Iran is not a pure realist state. It is a political order where ideology, clerical authority, and security imperatives have long coexisted in uneasy combination.The more dangerous possibility is not that realism replaces theology, but that realism gradually colonises it; that doctrine is not discarded but reinterpreted and subordinated to necessity, allowing the state to retain Islamic language while moving toward a posture the older Khamenei publicly resisted. If that happens, Iran’s nuclear future will be decided not only in centrifuge halls or command bunkers, but in the struggle between theological limits and strategic fear.The writer holds a PhD in Security Studies from Princeton University and is a senior IPS officer. Views are personal