Eyes on the Clock: What Comes Next for Iran’s Nuclear Program

Dr Ian Stewart, 22 June 2025

The attacks by Israel and the US on Iran's nuclear program have disabled and perhaps destroyed key facilities. While the next few days are likely to be consumed with analysis of the attacks and a possible Iranian response, with potential for escalation, thought must also now be given to the next steps on the nuclear file. In particular, we must keep an eye on the clock ahead of key October deadlines for UN Security Council resolution snapback. 

As things stand, the US and Israel have struck all of the known key nuclear facilities in Iran that could support a short-term breakout. This includes the enrichment sites at Natanz and Fordow and the nuclear fuel cycle facilities at Esfahan. Israel also targeted a number of key scientists. Unless Iran has already established secret sites not known to US or Israeli intelligence, the program will have been set back. However, since Iran has stocks of 60% Highly Enriched Uranium, Iran's breakout time continues to be measured in weeks even though the known facilities required to further enrich this material to near 90% and to convert it to metal are non-operational or destroyed. Iran could quickly reconstitute small-scale facilities to finish enrichment and convert the material to metal if needed. 

NPT and Safeguards

The broader questions are whether Iran will either withdraw from the Nuclear Nonproliferation Treaty (NPT) or hinder the International Atomic Energy Agency from implementation of safeguards under the NPT. These measures provide visibility into Iran's nuclear program to confirm that all nuclear material remain in peaceful activities. The IAEA has had questions about Iran's nuclear program for decades resulting in Iran twice being found in violation of its safeguards obligations. Nonetheless, Iran had been implementing important aspects of its safeguards obligations, which included inspectors on the ground at key facilities and an ability to verify the location of Iran's 60% HEU. That verification has been paused since Israel started its bombing campaign, meaning we do not know where Iran's HEU is. 

Iranian withdrawal from the NPT would be a significant step given that the NPT is viewed as the cornerstone of the international nonproliferation regime to which nearly every country in the world subscribes. Diplomatically, as a member of the non-aligned movement, Iran would no doubt paint the NPT as discriminatory and perhaps encourage other countries to exit in support of its own position. A broader withdrawal from the NPT would have broad negative effects for the nonproliferation regime. Still, withdrawal from the NPT itself does not mean a country will acquire nuclear weapons and the strikes on Iran's nuclear program itself will likely not change any country's nuclear calculus other than possibly Iran's. 

On the safeguards question, it is possible that Iran could simply allow the IAEA to continue its work. However, it is equally possible that Iran will obfuscate the location of the HEU. This could be predicated on the concern that if the location is known, Israel or the US could conduct military strikes on the location. Iran may also expressly refuse to implement its safeguards obligations on the basis that they are discriminatory. Iran may have been laying the groundwork for this with attacks on the head of the IAEA. 

UN Snapback

These issues are likely to take time to play out. There is however an important temporal dimension as the 'termination date' contained in the Joint Comprehensive Plan of Action - the Obama-era nuclear deal with Iran - is approaching in October 2025. While talk of the JCPOA may seem odd in current circumstances, it carries significance primarily because of the upcoming termination date and the snapback mechanism built into the JCPOA, which expires when that date is reached. The JCPOA was embedded into a Security Council Resolution 2231 which affords JCPOA participants the opportunity to reactivate the old UN sanctions resolutions on Iran should any party be in non-compliance with the JCPOA. The US withdrew from the JCPOA during the first Trump term and then tried to trigger snapback - something that was rejected since the US had already withdrawn. Other parties to the JCPOA though can still trigger snapback before October 2025, including the European participants. 

Snapback would reintroduce two key elements. The first would be the UN resolutions ordering a pause to Iran's nuclear program (and missile programs) due to its non-compliance with IAEA safeguards. The second is a monitoring and enforcement infrastructure including a committee of the Security Council which is tasked with monitoring adherence to the resolutions. The latter also includes the UN sanctions measures themselves. 

Importantly, snapback can be triggered by the Europeans without the agreement of Russia or China. It is thus perhaps the only foreseeable way to introduce Security Council resolutions on Iran.

Eyes on the Clock: Timelines for Diplomacy

There is almost certainly a round of diplomacy to come. While the parameters of that round depend to some extent on Iranian actions concerning the NPT, the key question will likely be whether Iran will agree to ship the HEU out of the country and accept constraints on its enrichment program. 

The incentive available to Iran would be to avoid UN sanctions snapback. However, while snapback is partly a punitive measure because of the sanctions it contains, it is also a useful backup monitoring mechanism as it creates a UN apparatus to constrain and monitor Iran's nuclear development. If Iran was to withdraw from the NPT, this UN mechanism would be the primary international instrument to monitor Iran's nuclear status. This mechanism can include the creation of a UN panel of experts to monitor implementation of the resolution's requirements, although such a panel would support the 1737 Security Council Committee and Russia may block its appointment in that forum. 

Thus, should Iran withdraw from the NPT before October, it seems certain that snapback would be triggered.  Iran may thus try to stall until after the termination date. On the other hand, if Iran does not provide the IAEA access to the HEU for verification purposes and does not negotiate in good faith, the Europeans should trigger snapback. 

The Europeans and the US should also seek to negotiate a longer-term mechanism that keeps the Iranian nuclear file active on the Security Council's agenda. Presently, the only way to do this would be with snapback. While it presently seems unlikely, it is possible that the Security Council members could agree to replace UNSCR 2231, including its snapback provisions, with a new resolution that provides for ongoing oversight of the Iran file. 

Ultimately, regardless of the path, it seems certain that the UN Security Council will become a key forum for the next steps in the Iran nuclear file.