War on Iran: nuclear consequences

President Donald Trump declared in his State of the Union address that he would see to it that Iran would never get a nuclear weapon. He had previously claimed that the strikes in 2025 had “obliterated” Iran’s nuclear programme, although there is evidence that the destruction might not have been as absolute as he claimed. Iran’s decision to again take part in negotiations on its nuclear programme with the Trump administration, despite the attacks in 2025, perhaps showed a desire to get back on an even keel internationally and end the crippling sanctions on the country.

It is important to remember that — whatever one might think of the Iranian regime and its appalling human rights record — it remains a member of the Non-Proliferation Treaty and has consistently declared its renunciation of nuclear weapons. Until the United States under the Trump administration withdrew from the Joint Comprehensive Plan of Action (JCPOA), sometimes called the “Iran Deal”, the threat of Iran changing its non-proliferation policy had diminished. 

However, before the next round of negotiations could even begin, a fresh wave of attacks by Israel and the USA on Iran began, a war that Trump says will last weeks and others fear will last substantially longer. The latest mission, according to him, is to prevent a rebuilding of the nuclear sites, to destroy their capability to hit targets with long-range missiles, destroy their navy and their “terrorist proxies”.

So, is the threat from Iran as clear and present as Israel and the USA are currently presenting it? In February 2026, US Special Envoy to the Middle East, Steve Witkoff, claimed that Iran is only a week away from having “industrial-grade bomb-making material” and that they were enriching to 60%. The Jerusalem Post was sceptical, pointing out that — after the June 2025 bombing — „Iran currently has no access to its material, no machines to enrich it, and no weapons program to use it“. The US and Israel have also killed most of its leading scientists. Matthew Bunn of Harvard Kennedy School is somewhere between the two, pointing out that no-one really knew what happened to the HEU stockpiled before the attacks, although Trump claimed they were destroyed. Bunn says trucks were seen at the sites before the strikes that could have moved the HEU elsewhere.

Two sites remain deeply buried: at Natanz and Isfahan. Natanz was hit on March 2, according to reports from Iran, but there is no clear assessment of the damage. The IAEA says that entrances to the underground plant were struck, perhaps in an attempt to close off access to them. However, it is unlikely that underground facilities can be destroyed from the air, even by “drilling down” by repeatedly bombing using earth penetrators.

Iran’s missiles can reach Israel and other countries in the region, but the claim that they can reach the United States has not been substantiated by intelligence sources. The unclassified US Defense Intelligence Agency assessment from 2025 states that Iran would need another ten years to viably reach the continental USA with an intercontinental ballistic missile. There are, however, multiple targets they can reach with current missiles, both in the region and in Europe, including US bases.

If this war does not lead to the regime falling, then it is likely that it will want to build nuclear weapons to deter further attacks. Now that Ayatollah Ali Khameini, Iran’s supreme leader, is dead, as well as several high-ranking officers of the Islamic Revolutionary Guard Corps, the question is: who is leading Iran and what will that mean for the country’s nuclear policy? A three-person leadership council is filling the vacuum, saying that the regime had prepared for this scenario, to choose the next Supreme Leader. It will also decide whether Ali Larijani, the state national security official, will continue in his role as decision-maker on defence, as he did last June.

Given that Iran is under attack, Khamenei’s successor is likely to be a hardliner and not a reformer. The regime may go all out to survive and rush to build a simple nuclear bomb with what material it may have amassed. Another possibility is that it will simply claim to have a nuclear deterrent and threaten to use it if the attacks continue.

In the event that the regime falls, Crown Prince Reza Pahlavi is waiting in the wings to return to Iran and take over leadership of the country. He already published his plan for the nuclear programme last year. In his “Emergency Phase Booklet” he sets out how international verification and transparency will be implemented: letting the IAEA back in to all nuclear sites to inspect them, and all outstanding issues will be addressed. Compliance with the NPT, as well as signing the Additional Protocol, would make Iran a good-faith partner internationally. In the long-term, Pahlavi has said he is willing to evaluate the future of using nuclear energy for Iran, and suspending activities at Bushehr in the time needed to review the situation, environmentally and in terms of security.

While these plans sound attractive internationally, both to governments and NGOs working on nuclear disarmament, regime change is a very risky business, as we have witnessed in Iraq and Libya. A regime under attack is about as dangerous as it can get, also for anyone opposing it. And how far are Israel and the USA willing to go to ensure that they reach their war goals? Those goals are by no means clear and seem to be fluid. Gaza has shown that sustained bombing against an adversary that has bunkered down will only destroy the civilian population. Iraq has shown us that regime change from the air is almost impossible.

Finally, the question arises yet again — as it also did with Iraq and Libya — is it better for a state to secretly develop nuclear weapons to protect itself against attack by nuclear-armed enemies? North Korea and Russia have shown that up until now, nuclear deterrence is keeping its adversaries at bay. Whether that remains the case and what the cost is, both financially and in terms of escalation and brinkmanship, is a fundamental question, given the catastrophic consequences should deterrence fail.

Sources:

Al Jazeera Staff, AP, Reuters: IAEA confirms buildings damaged at Iran’s Natanz nuclear facility, Al Jazeera https://www.aljazeera.com/news/2026/3/3/iaea-confirms-some-damage-to-irans-natanz-nuclear-facility

Bob YJ, Siegal T: Iran could be close to enriching uranium for bomb-making material, US envoy Steve Witkoff claims, The Jerusalem Post, 22.02.2026 https://www.jpost.com/middle-east/article-887433

Bunn M: Trump’s war on Iran: grave dangers and, at best, limited benefits, Bulletin of Atomic Scientists, 28.02.2026 https://thebulletin.org/2026/02/trumps-war-on-iran-grave-dangers-and-at-best-limited-benefits/#post-heading

Edwards C: Who’s running Iran now that the supreme leader is dead? CNN World, 01.03.2026 https://edition.cnn.com/2026/03/01/middleeast/iran-new-supreme-leader-khamenei-dead-intl-latam

Iran Prosperity Project: Emergency Phase Booklet, National Union for Democracy in Iran (NUFDI), February 2026 https://iranopasmigirim.com/EmergPhase_EN.pdf

Landay J, Pamuk H, Slattery G: Trump Iranian missile claim unsupported by U.S. intelligence, say sources, Reuters, 27.02.2026 https://www.reuters.com/business/aerospace-defense/trump-iranian-missile-claim-unsupported-by-us-intelligence-say-sources-2026-02-27/

PBS News: Read Trump’s full statement on Iran attacks, 28.02.2026 https://www.pbs.org/newshour/world/read-trumps-full-statement-on-iran-attack

Penley T: Witkoff warns Iran is ‚a week away‘ from ‚bomb-making material‘ as Trump weighs action, Fox News, 22.02.2026 https://www.foxnews.com/media/witkoff-warns-iran-a-week-away-from-bomb-material-trump-weighs-action

Razavimaleki V, Caplan M: With Khamene dead, Crown Prince Pahlavi could be Iran’s next leader. What would it mean for nuclear security? Bulletin of Atomic Scientists, 02.03.2026 https://thebulletin.org/2026/03/khamenei-dead-pahlavi-iran-next-leader-nuclear-security/#post-heading

Xanthe Hall was co-director, disarmament expert, and international campaigner for the German affiliate of IPPNW. She retired in 2025.