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Analysis//0022/May/2026/London-Dialogue. 16 May 2026
Introduction
The June 2025 and February 2026 strikes on Iran have prompted a rapid revision of conventional wisdom on nuclear weapons. A growing chorus of commentators argues that the unimpeded penetration of Iranian airspace by Israel and the United States, the targeting of senior leadership, and the systematic degradation of Iranian nuclear infrastructure demonstrate that a state can defend itself against nuclear powers without acquiring nuclear weapons of its own. The corollary, increasingly voiced in policy circles from Washington to Brussels, is that the deterrent value of nuclear arsenals has been overstated and that conventional precision, layered air defences, and diplomatic alignment can substitute for the bomb. The old Sagan-Waltz debate over whether more nuclear weapons make the world safer is, on this reading, being decisively closed in Sagan’s favour.
This reading is wrong. It universalises the wrong case study. Iran’s strategic predicament is structurally exceptional, shaped by geography, doctrine, and regional politics that do not obtain elsewhere. Read the Iran war alongside the Korean Peninsula, the Israeli-Arab balance, the US-Russia relationship in the shadow of Ukraine, and the May 2025 India-Pakistan crisis, and the opposite conclusion emerges. The Iran war did not disprove the logic of nuclear deterrence. It demonstrated, brutally, what happens to a regional power that has tried to substitute conventional and asymmetric capabilities for a nuclear hedge it never built.
The Iran Exception
Iran is not a generalisable case. For more than three decades, Tehran built a deterrent that deliberately bypassed nuclear weapons, relying instead on three pillars: a forward proxy network across Lebanon, Iraq, Syria, and Yemen; a large ballistic missile arsenal; and the implicit threat to close the Strait of Hormuz. The Institute for National Security Studies in Tel Aviv describes the twelve-day war of June 2025 as the moment when this entire architecture was tested and found wanting. The proxy axis had already been hollowed out by late 2024. The missile arsenal, though substantial, could not penetrate layered Israeli and American defences in sufficient quantity to inflict decisive damage. Air defences proved porous against fifth-generation aircraft and standoff munitions.
What remained was Hormuz. As the Middle East Council on Global Affairs has argued, Iran’s escalating efforts to disrupt navigation through the Strait reflect a deliberate attempt to weaponise economic geography in lieu of a credible military deterrent. Roughly a fifth of seaborne oil and liquefied natural gas transits this chokepoint each year, and the House of Commons Library records that shipping fell to around five per cent of pre-conflict levels after the February 2026 strikes. This is a singular geographic asset. No other regional revisionist power sits astride a comparable artery of the world economy.
The Gulf Arab states complicate any wider lesson further. Saudi Arabia, the United Arab Emirates, Qatar, and Bahrain cannot absorb a prolonged regional war. Their economies, basing arrangements, and energy revenues are exposed in ways that constrain even Western escalation. The Critical Threats Project notes that Tehran is now actively trying to convert this regional fragility into deterrent leverage of last resort, having lost almost everything else. None of these factors are reproducible. The Iranian model failed not because nuclear deterrence is obsolete, but because Iran’s substitute for nuclear deterrence proved structurally inadequate to its strategic ambition.
North Korea: The Clearest Counter-Case
The cleanest empirical rebuttal to the nuclear irrelevance thesis stands on the Korean Peninsula. Despite seven decades of US conventional superiority, a formal armistice rather than a peace treaty, repeated provocations, and an explicit American doctrine of denuclearisation, North Korea has not been attacked. The reason, as RAND’s Bruce Bennett has argued, is that Kim Jong-un’s nuclear arsenal has made regime survival the binding constraint on US and South Korean planning. Pyongyang’s 2022 nuclear law and subsequent doctrine, which formally authorise pre-emptive use under specific conditions, have not invited military attack. They have hardened the deterrent shield around the regime.
North Korean officials have been explicit about the comparative lesson. As the Stimson Center records, Pyongyang has repeatedly cited Iraq and Libya as warnings about the fate of states that abandon or never acquire nuclear weapons. The 2025 US Intelligence Community Annual Threat Assessment, summarised by the Congressional Research Service, describes nuclear weapons as the guarantor of regime security in Kim’s strategic calculus. Brad Roberts and colleagues at the Center for Global Security Research at Lawrence Livermore National Laboratory have shown that Pyongyang’s pursuit of de facto nuclear weapon state status is animated by precisely the survival logic that the Iran war has now made vivid. The Iran case does not refute the North Korean lesson. It reinforces it.
Israel: Existential Deterrence in Action
Israel’s posture of deliberate nuclear ambiguity, maintained for more than half a century, has been a quiet but indispensable structural variable in the 2025-26 war. Iran retaliated with hundreds of missiles and drones. It struck US bases, Gulf shipping, and Israeli infrastructure. It did not, at any point, attempt to threaten Israel’s existence as a state. The implicit knowledge that any campaign aimed at state destruction would invite a nuclear response set a ceiling on Iranian escalation, even as Iran’s regional deterrence collapsed beneath it. Israel’s nuclear weapons have not prevented every form of attack. They have prevented the catastrophic ones. That distinction, between deterring war and deterring existential war, is exactly what classical deterrence theorists from Bernard Brodie to Thomas Schelling claimed nuclear weapons could deliver and what the Al Habtoor Research Centre has identified as the asymmetric foundation of the current Israel-Iran balance.
US-Russia: The Cold Logic Holds
Three and a half years of war in Ukraine, the expiration of New START in February 2026, the resumption of nuclear test talk in Washington and Moscow, and the Trump administration’s August 2025 redeployment of nuclear submarines in response to Russian rhetoric, have not produced a direct US-Russia war. NATO has supplied Ukraine with progressively more capable weapons, but it has not crossed the threshold of direct combatant involvement. Russia has used nuclear signalling repeatedly, deployed non-strategic warheads in Belarus, and threatened escalation against Western capitals. Yet the American Academy of Arts and Sciences records what Nina Tannenwald has called the durability of the nuclear taboo, even in a conflict where one party has invoked nuclear weapons more freely than at any point since the Cuban missile crisis.
The Russia-Ukraine war does illustrate the stability-instability paradox. Nuclear weapons constrain decisive war at the strategic level while permitting prolonged conventional violence below it. But the strategic level is the level that matters for state survival. The fact that Moscow and Washington have avoided direct confrontation through a war of this scale in this neighbourhood on these stakes is not evidence that nuclear weapons are losing relevance. It is the opposite. As the Carnegie Endowment has detailed, both capitals are now investing heavily in new strategic systems, from Poseidon and Burevestnik on the Russian side to the Sentinel ICBM and Columbia-class submarine on the American side, precisely because each regards nuclear deterrence as the indispensable backstop of strategic competition.
India and Pakistan: Nuclear Weapons Avoiding Worst Outcomes
The May 2025 India-Pakistan crisis is now the most heavily studied conventional clash between two nuclear-armed states since Kargil. Following the April 2025 Pahalgam attack, India launched Operation Sindoor with deep strikes into the Pakistani heartland, including Punjab; Pakistan retaliated with Operation Bunyan al-Marsoos. As the Stimson Center compendium of analyses by Christopher Clary, Walter Ladwig, Arzan Tarapore, Sitara Noor, Tong Zhao, and Beenish Pervaiz makes clear, the four-day exchange reached levels of escalation previously unseen between two nuclear powers, including missile strikes on military targets within both heartlands.
Two observations follow. First, the war ended. A US-brokered ceasefire was reached on 10 May 2025, four days after the first Indian strike. Pakistan’s nuclear signalling, whatever its credibility problems, weighed on every escalatory decision India contemplated. The Bulletin of the Atomic Scientists is right that Indian planners are testing thresholds more aggressively than ever before, but the threshold remains. Neither capital crossed it.
Second, both states are now investing in survivability rather than retiring their deterrents. India is reinforcing its sea-based leg; Pakistan is consolidating central command and accelerating Babur-3 development. The lesson regional planners are drawing from the war is not that nuclear weapons are obsolete. It is that escalation control depends on credible second-strike capabilities, which is the orthodox conclusion of the deterrence literature from Vipin Narang’s work on nuclear postures back through Schelling. The 2019 Balakot strike, the 2025 Operation Sindoor pattern, and Pakistan’s quid pro quo plus doctrine collectively describe a sub-strategic instability that nuclear deterrence cannot eliminate but that has, in every crisis since 1998, stopped short of the strategic threshold.
Second, the Iran war has redistributed strategic gains in ways that benefit revisionist powers. Russia has absorbed an effective adrenaline shot from higher oil prices and the Western drawdown of Patriot interceptors, while China has secured a stronger negotiating position in Beijing. The cumulative effect is to deepen the perception, particularly in the Global South, that the United States is overstretched and that its alliance system is fissuring. The simultaneous arrival of European unease over Trump’s Greenland posture, Atlantic estrangement on Ukraine, and Indo-Pacific anxiety about Taiwan compounds the impression of a hegemon negotiating from receding ground.
Third, the rhetorical victory Xi extracted, the framing of bilateral relations as one of “managed competition” or “strategic stability”, is itself a strategic gain. It allows Beijing to define what conduct lies within acceptable competition and what crosses into instability, transferring interpretive authority from Washington to the joint communiqué. The accompanying invitation for Xi to visit the White House on 24 September 2026 institutionalises that dynamic for the rest of Trump’s term.
Conclusion: The Wrong Lesson from the Right War
The Iran war is genuinely significant for the global nuclear order, but not in the way the ‘irrelevance thesis’ suggests. As Chatham House and the Bulletin of the Atomic Scientists have both argued, the most likely proliferation lesson states will draw is the opposite of the one being promoted in some western capitals. Iran was attacked while at the nuclear threshold and during active negotiations. North Korea, having crossed the threshold, has not been attacked. South Korean policy debates over an indigenous nuclear deterrent are already shifting in response, as 38 North has documented.
For policymakers, the danger is asymmetric. Misreading the Iran war as evidence of nuclear irrelevance will not persuade Pyongyang to disarm, persuade Moscow to accept conventional defeat in Ukraine, persuade Islamabad to abandon full-spectrum deterrence, or persuade hedging states from Riyadh to Seoul to forgo a nuclear option. It will, however, encourage strategic complacency in the very capitals that need to fund modernisation, sustain extended deterrence commitments, and revive arms control before the post-New START vacuum becomes permanent.
The enduring logic of nuclear deterrence is not that nuclear weapons solve every security problem. It is that they make state destruction prohibitively costly and so set the outer limits of what adversaries can attempt. The Iran war is a brutal demonstration of what happens inside those limits when a state has no nuclear deterrent to draw on. The right lesson is not that nuclear weapons no longer matter. It is that, for the kind of high-stakes regional confrontations now defining global politics, they matter more than they have in a generation.
Dr Tahir Mahmood Azad is Executive Director of London Dialogue, an independent UK-based research and policy institute. He can be reached at [email protected]
Tahir Azad
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