The US Treasury secretary has announced what was described as an economic D-Day against Iran. The head of Iran’s Supreme National Security Council, Mohsen Rezai, responded that any country joining the United States in sanctions would be considered an enemy. Iran’s president, meanwhile, has publicly defended the memorandum of understanding with Washington as the best path forward.

Two Iranian positions, not one

The most useful thing in this exchange is that Tehran is saying two different things at once, and both are official.

The president is defending a negotiated instrument as the way out. The Supreme National Security Council is threatening third countries. Those are not compatible negotiating postures, and the gap between them is a fair indication that the argument inside the Iranian system has not been settled.

It is worth remembering where authority actually sits. Neither the president nor the Security Council secretary holds final say over war and peace; that rests with the supreme leader. Both statements are signals about internal debate rather than decisions, a distinction we set out in our piece on reading war rhetoric.

The threat to third countries is the operative part

Rezai’s statement is aimed at the mechanism that makes American sanctions bite. As we explained last week, the instrument that does the work is not the direct measure but the secondary one — penalising third-country firms that keep trading with the target, which forces banks everywhere to choose between the target and access to dollar clearing.

Declaring participating countries enemies is an attempt to raise the cost on the other side of that choice. Whether it works depends entirely on whether any government finds the threat more consequential than losing access to the American financial system, and historically very few have.

The audience is presumably the states still buying Iranian crude, above all China — where offers have already fallen under the naval blockade, as we reported.

The memorandum that keeps reappearing

The president defending the memorandum of understanding as the best path forward is the more surprising element, because that instrument expired without extension a week ago.

A memorandum of understanding is not a treaty. It records what parties say they intend, generally without creating binding legal obligations — which is precisely why states reach for one when a treaty is unavailable, and why it settles less than the attention it receives suggests.

Defending a lapsed instrument in public is a way of keeping a negotiated route on the table without proposing anything new. It is also, read another way, an argument aimed inward — at Iranian officials who regard negotiation itself as the mistake.

What “economic D-Day” would have to contain

An announcement is not a measure. The things that would make this real are checkable and public: named entities appearing on designation lists, secondary sanctions extended to new sectors, third-country banks visibly withdrawing, and whether any humanitarian carve-out is issued for food and medicine.

Iran has been under extensive sanctions for many years, which limits how much a new round can add, and the strait is already largely unusable — meaning ordinary commerce is being disrupted by the conflict rather than by any legal instrument. Until the designations appear, the phrase describes an intention.

Sources

• Anadolu Agency — morning briefing, 24 August 2026
• CBS News — live updates, including Rezai’s statement and the president’s defence of the memorandum