On August 28, the Europeans triggered the nuclear sanctions snapback mechanism. On September 19, the Security Council failed to block it. By September 27, the pre-JCPOA (2015 Iran nuclear deal) UN sanctions on Iran will return automatically.
There is no further debate. The only question is whether governments will translate the legal mechanism into enforcement or allow it to fade into symbolism.
The snapback restores the sanctions that were lifted in 2015: the arms embargo, restrictions on ballistic missiles, travel bans, asset freezes, mandatory cargo inspections, and financial vigilance obligations.
These are not abstract provisions. They are operational authorities designed for use by governments that choose to act: interdicting shipments, freezing accounts, and denying officials the ability to travel. If applied with discipline, they cut the Iranian Revolutionary Guard Corps’ access to money, weapons, and technology. If neglected, they confirm Tehran’s calculation that the West announces penalties but never enforces them.
Iran’s leaders are already signaling confidence. President Masoud Pezeshkian has claimed that the country can withstand a return of sanctions. That assumption rests on divided democracies, Russian and Chinese obstruction, and the networks of shadow fleets and front companies that have allowed the regime to move oil and procure sensitive goods.
Tehran is betting that Western governments will lack the will to act decisively. If it is correct, the snapback will be another empty gesture. If it is wrong, this moment will become the turning point that constrains Iran’s nuclear advances and regional aggression.
The value of the snapback is not in restarting negotiations. Talks have provided cover for Iran to advance enrichment and arm its proxies. The value lies in giving governments the legal basis to enforce measures already designed and tested. The West does not need new institutions or authorities. It needs to instruct the bureaucracies that already regulate shipping, insurance, banking, and customs to apply the rules on the books.
How the West can make the snapback credible
These are the steps that the West can take to make the snapback credible. Joint advisories from insurers and flag registries should immediately revoke coverage and registration for Iran-linked vessels, forcing tankers into idleness.
Port-state control authorities at critical chokepoints such as Suez, Gibraltar, Fujairah, and Singapore can add sanctions checks to their existing inspection regimes, detaining cargo and ships engaged in prohibited trade.
Clearinghouses and central banks can block transactions tied to Iranian crude, petrochemicals, and metals, making access to Western financial markets incompatible with facilitating Iran’s exports.
Customs services should be equipped with a procurement watchlist covering drone and missile components, complete with part numbers and vendor names, to raise interdiction success rates.
National authorities should synchronize UN snapback lists with US, EU, and UK designations, ensuring that IRGC companies and their fronts face consistent restrictions across jurisdictions. Enforcement should be measured: governments should publish monthly data on ships detained, accounts frozen, and procurement networks dismantled.
Every missile component stopped under the snapback mechanism is one less weapon in Hezbollah’s arsenal or in Houthi drones aimed at Persian Gulf infrastructure. Regional security depends on treating snapback as an operational mandate, not as a press release. For Israel, Persian Gulf partners, and Europe alike, enforcement is the only way to prevent Iran’s advances from becoming battlefield realities.
Washington must anchor this process. Only the United States can combine financial dominance with maritime power to ensure snapback is binding in practice. US leadership, paired with European alignment and Israeli and Arab partners’ operational reach, can turn the return of sanctions into sustained pressure.
Additional measures can follow once the first layer of enforcement is established. Secondary sanctions can be extended to banks and traders that continue to facilitate Iranian exports. Aviation regulators can deny overflight and landing rights to Iranian carriers linked to sanctions violations.
The European Union can join the United States, the United Kingdom, and Canada in designating the IRGC as a terrorist organization, aligning counterterrorism tools with nonproliferation enforcement. Democratic partners can establish a “2231-plus” coalition – an enforcement cell to share intelligence, coordinate interdictions, and sustain pressure long after Resolution 2231 formally expires on October 18.
Iran will threaten escalation. It will raise enrichment levels, obstruct inspectors, and activate its proxies. The correct response is not accommodation but intensified enforcement.
If inspectors are expelled, the response should be to expand export controls and interdictions. If enrichment increases, the response should be to dismantle procurement networks. If proxies strike, cut supply chains and expose the conduits publicly. The worst possible signal is to turn threats into bargaining leverage.
By September 27, the sanctions will be back in force. On September 28, the test begins. The law has spoken. Enforcement is now the only policy test that matters.
The writer is an energy and industrial policy expert and a political and human rights advocate. Follow him on X: @Aidin_FreeIran.