Snapback – the reintroduction of UN sanctions against Iran – restored the legal framework for sanctioning Iran’s oil trade, but a law without enforcement leaves the system hollow. Despite the reimposed measures, Iran continues to move crude and condensate to China through deceptive shipping, opaque finance, and oil-for-projects barter deals.
The answer is not symbolic shows of force in the Strait of Hormuz, but disciplined, intelligence-led maritime enforcement targeted inspections of Iran-linked tankers in lawful waters, executed through cooperative frameworks under international law.
Why this approach is necessary
This approach is necessary for three reasons. First, stopping every vessel in major waterways like the Strait of Hormuz would violate international law and fracture coordination among flag states and maritime partners.
Intelligence-led inspections, conducted with flag-state consent at sea or by Port State Control (PSC) at the next port of call, are lawful, replicable, and effective.
Second, deception now occurs outside Hormuz through Automatic Identification System (AIS) dark periods, identity cloning, ship-to-ship transfers, and rapid flag changes in the Gulf of Oman, the Arabian Sea, and the western Indian Ocean. Enforcement must shift to those waters where concealment actually happens.
Third, the challenge extends beyond the vessels themselves. Each voyage depends on a supporting value chain, including insurers, classification societies, shipyards, bunkering firms, terminals, and financial intermediaries – all of which provide points of lawful leverage. Pressure must land on every link in that chain.
These mechanisms already exist under United Nations Convention on the Law of the Sea (UNCLOS), the International Convention for the Safety of Life at Sea (SOLAS), and the Paris and Tokyo Memoranda of Understanding (MoUs) on Port State Control, providing the legal foundation for inspections and detentions when deception is proven.
Iran has perfected the art of cheating in plain sight. Its networks of shell companies, front operators, and reflagged vessels function not because they are clever, but because enforcement is inconsistent.
Every time Washington issues sanctions without follow-through, Tehran learns that defiance pays. The Islamic Republic’s playbook has not changed in decades; it counts on distraction and the illusion of complexity to outlast Western will.
The tools are already there
The tools to stop this are already in place. Intelligence cooperation through maritime security centers in Bahrain, Singapore, and Athens, operating under the Tokyo and Paris Memoranda of Understanding on PSC, already enables allied navies and port authorities to share real-time data on high-risk tankers.
Europe can tighten PSC inspections and insurance oversight, India can monitor bunkering and port calls, and Japan can strengthen compliance within classification and shipyard networks.
Flag-state inspections and PSC regimes under UNCLOS, SOLAS, and International Convention for the Prevention of Pollution from Ships (MARPOL) provide lawful grounds to detain deceptive ships without confrontation.
When enforcement becomes systematic rather than sporadic, evasion turns costly, insurance premiums rise, and Iran’s export margins shrink.
The financial front must advance in parallel. Tehran’s barter-finance system, which trades oil for infrastructure projects or goods from Chinese contractors, bypasses banking channels and hides within commercial contracts.
The US Treasury and its partners, working with the Office of Foreign Assets Control (OFAC), should issue a Financial Crimes Enforcement Network (FinCEN)-style advisory and update the OFAC shipping advisory, labeling barter settlements as high-risk exposures and directing enhanced due diligence expectations for Protection and Indemnity (P&I) Clubs, insurers, and classification societies.
Once compliance departments treat Iran-linked cargoes as toxic assets, traders and insurers will walk away voluntarily. That is how enforcement turns from legal theory to market reality.
The role of transparency
Transparency should complete the strategy. Publishing regular enforcement data creates visible consequences. Markets respond to clarity. When violators see measurable penalties, deterrence becomes self-reinforcing. Iran’s oil trade thrives in ambiguity; it falters under light.
Recent detentions and insurance cancellations in European and Asian ports have already shown that predictable, rules-based enforcement can raise costs and reduce Iran’s export margins without provoking confrontation.
Focused, lawful enforcement achieves what military posturing cannot: it cuts Tehran’s revenue while avoiding escalation. The United States should lead through steady, rules-based application of existing law and coordinated action with partners that share exposure to Iran’s deceptive trade networks.
Snapback created the law; enforcement must supply the will. Iran cheats because it can. The United States and its partners can change that reality without firing a shot or closing a single shipping lane.
The test now is not whether sanctions exist, but whether Washington has the resolve to make them mean something.
The writer is an energy and industrial policy expert. Follow him on X: Aidin_FreeIran.