Iran’s dramatic advances in its enrichment programme—most notably enrichment to 60% using advanced centrifuges—had placed Tehran only a short technical step away from weapons-grade enrichment at 90%. At the same time, intelligence indicated parallel progress in weaponisation-related activities, significantly shortening Iran’s breakout timeline should the Supreme Leader decide to pursue a bomb.
Against this backdrop, in June last year, Israel launched a pre-emptive campaign aimed at disrupting Iran’s path to a nuclear weapon. The operation focused on assassinating key nuclear scientists associated with weaponisation efforts, alongside extensive damage to Iran’s enrichment infrastructure at Natanz and Isfahan, including the destruction of the uranium conversion line. Most notably, the heavily fortified Fordow facility was struck by U.S. B-2 bombers, marking an unprecedented level of American operational involvement in Israeli military strikes against Iran.
There is little doubt that these strikes were highly effective. In practical terms, they rolled Iran’s nuclear programme back by several years and severely degraded its industrial-scale enrichment capability. Yet despite these achievements, Iran’s nuclear challenge remains fundamentally unresolved.
First, the strikes were unable to eliminate Iran’s stockpile of highly enriched uranium—estimated at roughly 409 kilograms enriched to 60%. This material alone represents a critical strategic asset that dramatically shortens Iran’s breakout time. In fact, as a result of the attacks, the International Atomic Energy Agency (IAEA) lost control over that uranium.
Second, Iran retains not only centrifuges but, more importantly, the accumulated knowledge and expertise required to rebuild its enrichment programme. Even without a large industrial infrastructure, a smaller and more clandestine setup could allow Iran to enrich uranium to weapons-grade levels within a matter of months.
The same logic applies to weaponisation. Iran possesses a deep and resilient scientific base, and the loss of specific personnel—however significant—does not erase decades of accumulated know-how. Nuclear weapons technology is mature and well understood, and Iran has already crossed many of the key technical thresholds in the past.
In this sense, the Israeli-US campaign—precisely because of its effectiveness—highlights a strategic paradox: military force can delay and disrupt a nuclear programme, but it cannot erase nuclear knowledge from a determined state. Moreover, the campaign has incurred high strategic costs. Iran has suspended cooperation with the IAEA, leaving the international community increasingly in the dark about developments on the ground. At the same time, the strikes may strengthen voices within Iran’s leadership arguing that only a nuclear weapon can restore deterrence after what they perceive as a profound strategic humiliation.
The Israeli-US campaign—precisely because of its effectiveness—highlights a strategic paradox: military force can delay and disrupt a nuclear programme, but it cannot erase nuclear knowledge from a determined state. Danny Citrinowicz
As Iran begins repair efforts at damaged sites and reportedly advances new hardened facilities—such as those near Mount Kolang Gaz La—the limitations of kinetic action become even clearer. If Iran’s leadership ultimately decides to acquire a nuclear weapon, military strikes alone are unlikely to prevent that outcome.
The central policy lesson for Washington is therefore sobering: while military action can buy time, it cannot substitute for a broader strategy. Any sustainable approach to the Iranian nuclear challenge will require a combination of deterrence, diplomacy, intelligence, and—crucially—clear political objectives regarding the desired end.
It is important to underscore that Iran has earned the international community’s deep mistrust through years of concealment, deception, and violations related to its nuclear programme.
For this reason, any oversight of Iran’s nuclear activities conducted by the IAEA must be intrusive, rigorous, and comprehensive. Such oversight, that was part of the JCPOA safeguards, should include frequent access to enrichment facilities, the deployment of continuous monitoring systems and remote surveillance at all sites associated with Iran’s nuclear programme, the authority to conduct short-notice inspections, and access to military sites where there is credible suspicion of nuclear-related activity. Many of these instruments were part of the JCPOA, which fell apart after the first Trump administration decided to no longer comply with it.
This monitoring regime must be implemented and enforced exclusively by the IAEA, carried out by inspectors with proven experience in the Iranian nuclear file, and without any Iranian influence over their selection, which would require a change of IAEA inspection procedures.
For its part, Iran may be prepared to accept such an intrusive inspection regime, provided it results in meaningful sanctions relief and preserves—at least symbolically—its claimed right to enrich uranium on its own soil. If these are the limits of the concessions demanded of Tehran, and they do not extend to constraints on Iran’s conventional military buildup or its support for regional proxy actors, Iran is likely to accept significant limitations on its nuclear programme alone.
The European Leadership Network itself as an institution holds no formal policy positions. The opinions articulated above represent the views of the authors rather than the European Leadership Network or its members. The ELN aims to encourage debates that will help develop Europe’s capacity to address the pressing foreign, defence, and security policy challenges of our time, to further its charitable purposes.
Image credit: Alamy, ZUMA Press, Inc.
