On June 15, 2025, Israel, claiming self-defense, launched what would become known as the 12-Day War with Iran. The attack occurred in the midst of a new phase in the ongoing US-Iran nuclear negotiations that appeared to be auguring well for an agreement over enrichment and sanctions relief. International Atomic Energy Agency (IAEA) inspectors were in Iran at the time assessing its nuclear facilities, as they had been almost every day that year. In nearby Oman, mediators were preparing for the sixth round of the talks scheduled for two days later. US intelligence had re-confirmed on March 25 that there was no indication Iran was building a bomb.
The Israeli attacks, followed within days by massive American bombing of Iran’s three main nuclear sites – Isfahan, Fordow and Natanz – abruptly ended both the IAEA’s inspections and the negotiations. The acts of aggression by two nuclear powers, Israel and the US, violated international law, and seriously threatened the viability of the Nuclear Non-Proliferation Treaty (NPT), to which Iran is a signatory. Even so, the Europeans, the architects of the first nuclear deal, the Joint Comprehensive Plan of Action (JCPOA), and who have been historically committed to diplomacy over military interventions, supported the offensive. German Chancellor Friedrich Merz lauded Israel for “doing the dirty work for all of us.”
Lessons from North Korea’s march towards nuclear weapons
Yet, the war did not achieve Israel’s goals – to derail Iran’s nuclear program and to destabilize its regime to the point of collapse. Instead, the 12-Day War may have achieved the opposite – pushing Iran toward nuclear weaponisation, a path it has consistently hesitated to take. Yet, Western pressure has inexorably induced Iran to move in that direction in a process not dissimilar to that which resulted in North Korea’s decision to acquire atomic weapons in 2013.
For Iran, three interlinked takeaways from the 12-Day War have changed the rationale for self-restraint and compliance with international treaties. First, the War illustrated that although Iran’s missile capabilities are significant and served well against Israel, it has no effective deterrence to avert another round of war. Second, the “good cop, bad cop” balance between the US and Europe (notably, the three signatories of the JCPOA: the E-3 – Germany, Britain and France) has shifted to a ‘bad cop, bad cop’ dynamic, with Europe conceding its mediator role and adopting the same demands as the US and Israel. Third, the War shredded the credibility of American assurances that negotiations could deliver security. Iran now has no incentive to reveal how much its nuclear program was damaged, or where it has stashed its 400-kilo stockpile of highly enriched uranium.
Harsh western diplomatic tactics could push Iran to the nuclear threshold
Unlike North Korea, which departed the NPT in 1993 and began conducting nuclear tests by 2006, Iran has proclaimed for decades that a fatwa from the Supreme Leader, Ali Khamenei, prohibits nuclear weaponisation as inhuman and un-Islamic. This may explain why Iran has taken longer than any other country with nuclear ambitions to develop an atomic weapon. Having begun in the 1950s with US President Eisenhower’s Atoms for Peace program, Iran didn’t develop enrichment capabilities until four decades later in the ‘90s. Iran’s program has since undergone cycles of expansion and constraint in response to a series of negotiations between 2002 to 2025. These included the 2015 agreement, the JCPOA, which led to broad IAEA inspections and full Iranian compliance under its terms until a year after President Donald Trump withdrew from the deal. Iran has also been under heavier IAEA monitoring and verification than any other nation. Based on a ‘don’t trust but verify’ premise, the JCPOA’s Additional Protocol required frequent inspections on short notice to ensure transparency. Even after the US walked away from the JCPOA, the NPT’s verification requirements still meant that monitoring remained robust: in 2024, the IAEA conducted 429 inspections in Iran.
True, Iran has been guilty of multiple breaches in transparency and compliance, as an IAEA resolution passed the day before Israel’s attack attested. However, as in the case of North Korea, US and European insistence on coercion as an accompaniment to diplomacy has consistently undercut goodwill and trust and instead, sown fear. For its part, Iran’s fear of US, Israeli and Western aggression has been fed by numerous tactics: the imposition of increasingly severe sanctions; ultimatums if new demands are not met (as in the newly revived requirement for ‘no enrichment’, a debate conducted and settled with the JCPOA); constant warnings that the military option always remains on the table; and repeated violations of international law – most recently with the Israeli and American unprovoked attacks on Iran’s territory in the 12-Day War. All these tactics, along with demands for Iran to “change its behaviour,” and pointed encouragement to the Iranian public to undertake regime change (most recently by Prime Minister Netanyahu the day he attacked Iran) have prodded Iran further along the path to nuclear threshold status.
As frequently pointed out by the Europeans when the JCPOA was agreed, diplomacy offers the only long-term solution because it achieves agreement by both parties. Military counter-proliferation, from Israel’s attack on Iraq’s nuclear program at Osirik in 1984 to the 12-Day War, only stalls nuclear ambitions; it does not stop them.
Europe’s threats and failure to hold up its end of the bargain
Yet, neither the US or Europe appear ready to practice the lessons learned from either the North Korea experience or the Iran case. Tension now is building around the impending threats by the JCPOA’s European signatories to revive the moribund deal’s ‘snap-back’ mechanism and re-impose UN sanctions on Iran before the JCPOA expires in October. The E-3’s insistence that the US and Iran strike a deal before the end of August politicises the legal instruments of the JCPOA, which nuclear policy commentators Sahil Shah and Nathalie Tocci view as purely a ploy to increase European leverage, especially as Iran was never awarded similar rights under the deal to challenge Western non-compliance, most obviously through Trump’s departure from the JCPOA.
The E-3 justify imposing the snap-backs because Iran is non-compliant. In reality, Iran was fully compliant with the JCPOA when the US left the agreement in 2018. In leveraging the snap-back mechanism in the JCPOA, France, Britain and Germany are overlooking their own non-compliance in having failed to ensure sanctions relief to Iran when the US abandoned the agreement. They are also ignoring the blowback Iran suffered as an emboldened Israel took advantage of the US withdrawal to begin assassinating Iran’s nuclear scientists and targeting its infrastructure and nuclear facilities – a practice that reached an apex during the 12-Day War and continues today even after the Trump-imposed ceasefire between Israel and Iran.
Iran has not abandoned further hopes of negotiation. Its Foreign Minister met in late June with the Europeans in Istanbul about the snap-backs, and has invited the IAEA to Tehran to discuss new modalities for future inspections. Yet Europe, according to Hassan Hanizadeh, a conservative analyst writing in Setareh Sobh, “is attempting to impose the West’s conditions on Iran. The US is allowing Israel to carry out military actions against Iran, while Europe pushes those same goals through negotiations.” No more the mediator, Europe, in the view of many Iranian commentators, is signalling its support for a coercive turn in strategy, insisting on zero enrichment, and renouncing its commitment to diplomacy.
In Iran, the prospect of snap-back sanctions further hobbling its beleaguered economy is raising alarm, as well as giving new opportunity to those arguing for developing at last, a real nuclear deterrent. Erfan Alamshahi, of the Tehran Institute, an international affairs think tank affiliated with the University of Tehran, argues that current conditions are uniquely favourable: “Social cohesion inside the country is high; public demand for building such a weapon is growing; IAEA inspections are suspended; and Trump is momentarily distracting global attention by [claiming] the destruction of Iran’s nuclear facilities. What Iran needs more than technical capability is a political decision.” Yet Alamshahi acknowledges that so far, Iran’s leadership has not made the decision to weaponise, despite the 12-Day War’s clear demonstration, in his view, that Iran needs an effective deterrent against further large-scale attacks.
In stark contrast to Israeli Prime Minister Benjamin Netanyahu’s expectations that the War would lead to regime disintegration, Iran experienced a surge in national patriotism as the War unfolded, with many Iranians expressing outrage at the assassination of their military leaders and the destruction in Tehran, and pride at the effectiveness of the military’s retaliation against Israel. Government rhetoric has since focused on Iran’s courage and strength with little use of Islamic language, and there has been a notable tolerance for social freedoms, including women’s choice not to wear the veil, even as the government has moved ruthlessly to plug the obvious holes in its intelligence system. As Johns Hopkins expert Vali Nasr observed, “Defense of the country didn’t need hijab, it needed patriotism.”
Concern however is high that a second round of attacks is imminent, with the Revolutionary Guards and the Atesh, the national army, on high alert. A bill withdrawing Iran from the NPT was debated on June 16 in the parliament, the most recent expression of a groundswell among the population in support of nuclear armament, and followed an official threat made earlier that if snap-backs were imposed, Iran would consider departing the NPT. If Iran were to withdraw, it would not only seriously undermine the Treaty as the foundation of the global nuclear order. It would legally free Iran to pursue a nuclear weapon. However, counterarguments note the dangers, including the lack of secrecy, and the need for not only missile delivery, but also bombers and submarines, for effective deterrence. Iran currently lacks the latter two, despite talks with China and Russia to fill those gaps.
Trump must shift gears and shore up trust with Iran
Most critical to the equation will be US President Donald Trump’s next steps and his ability to shift from credible threats to credible assurances. Press reports in both Iran and the US hint another round of nuclear negotiations may be forthcoming, but Iran has made talks conditional on security guarantees that ensure neither Israel nor the US will attack Iran if negotiations go forward. In Rosemary Kelanic’s view, expressed in a recent Carnegie Endowment interview, “If the United States truly wants to prevent Iran from ever getting the bomb, it needs Iran’s cooperation to ascertain the status of its program and physically dismantle it in a monitored, verifiable way. But Iran has no incentive to cooperate with the United States unless it thinks it will avoid future punishment by doing so—and that is where the need for assurances comes in.”
Yet, Trump’s bargaining approach typically is conducted on public platforms in which he offers a succession of big benefits, ultimatums and threats, a technique that presents a deal without engaging with the other party. By insisting on no enrichment, a demand for which Iran has found work-arounds in the past and for which it suggested options that were to be discussed in Muscat, Trump is ignoring the significance to national pride and the Iranian economy that enrichment represents. As Nasr describes it, “Enrichment is to Iran’s market what the car industry is to Germany’s.” Yet, unless Trump can shift gears to shore up trust, and offer credible assurances that soft, rather than hard power is central to the US strategic plan to incentivise Iran to denuclearise, the pressure on Iran could hasten its decision to pursue a weapon. It has the technical capacity, and the hidden stockpile, as Israel rattles its sabres for another round of war. And if Iran takes that step, the West will be complicit in pushing a 10th nation toward nuclear armament rather than non-proliferation.
Dr Roxane Farmanfarmaian is Director of International Studies and Global Politics at the University of Cambridge Institute for Continuing Education and teaches at the Department of Political and International Studies (POLIS). She is a Senior Associate Fellow at the Royal United Services Institute (RUSI), a member of the European Leadership Network’s Iran group which focuses on the nuclear deal (the JCPOA), and often comments for the media on Middle Eastern and Iranian Affairs.
