Trump Holds Iran Blockade Through Nuclear Deal Certification

President Trump has declared the U.S. naval blockade of Iranian ports will remain in force until a nuclear agreement is “reached, certified, and signed,” rejecting Iran’s proposal for expedited relief and locking sustained economic pressure on Tehran through the final stages of negotiations.

The policy statement, issued according to CNBC on 24 May, clarifies that blockade enforcement will extend through certification — a process that could take weeks beyond any provisional agreement. This represents a hardline departure from the 60-day framework outlined in draft terms circulating among negotiators, where Iran expected early Strait of Hormuz reopening in exchange for nuclear talks.

The blockade has already redirected 100 commercial vessels over six weeks, according to U.S. Central Command data published by Bloomberg on 23 May. More than 240 ships remain queued outside Iranian waters awaiting permission to transit the Strait of Hormuz, while only 33 vessels — including oil tankers — passed through with Iran’s approval in a 24-hour period ending Saturday.

Certification Conditionality Extends Leverage

The blockade-through-certification requirement effectively extends U.S. enforcement weeks beyond any provisional deal signature. According to Axios, draft terms envision a 60-day ceasefire extension with Strait reopening, Sanctions waivers, and Iranian oil sales permitted — but Trump’s insistence on maintaining blockade until final certification introduces a reversibility mechanism absent from earlier frameworks.

A U.S. official described the approach as “relief for performance,” making clear the deal could collapse before the 60-day window closes if Washington judges Iran insufficiently committed to Nuclear Negotiations. Trump himself told Axios in April he would keep the blockade in place until Iran addresses U.S. nuclear concerns: “I don’t want to [lift the blockade], because I don’t want them to have a nuclear weapon.”

Iran’s chief negotiator, Mohammad Bagher Ghalibaf, rejected the framing, stating per CNN that “Iran will not back down from the rights of our nation and country — especially when dealing with a party that has never shown sincerity.” Tehran has consistently called for upfront Strait reopening before committing to nuclear timelines, a sequencing Trump explicitly rejected.

Energy Markets Price Indefinite Disruption

North Sea Dated crude traded around $110 per barrel in May, according to the International Energy Agency, with cumulative supply losses exceeding 1 billion barrels since the Strait closure began in March. The IEA calculated 14+ million barrels per day of oil remain shut in — roughly 14% of global supply — as the blockade and Strait disruption compound.

When the blockade took effect on 13 April, U.S. crude futures for May delivery rose to $99.08 per barrel and Brent June delivery settled at $99.36, before climbing further on sustained enforcement. Trump has claimed the blockade costs Iran $500 million daily; the Defense Department estimated the revenue loss at $4.8 billion by 1 May.

Regional Pushback on Strait Leverage

Israeli officials privately warned the draft agreement signals Iran has weaponised control over the Strait of Hormuz as effectively as nuclear capability. An anonymous Israeli official told NPR the emerging framework is “bad because it signals to the Iranians that they possess a weapon no less effective than a nuclear one, and that is the Strait of Hormuz.”

Republican lawmakers echoed the concern. Senator Ted Cruz stated it “would be a disastrous mistake if an agreement resulted in Iran being able to develop nuclear weapons and have control over the Strait of Hormuz.” The criticism reflects anxiety that expedited Strait reopening without irreversible nuclear concessions leaves Iran with leverage to repeat the closure.

Vice President JD Vance reinforced the administration’s position, stating during failed Islamabad talks in April: “The simple fact is that we need to see an affirmative commitment that they will not seek a nuclear weapon.” The blockade-through-certification policy operationalises that demand by withholding relief until Tehran makes binding commitments subject to U.S. verification.

What to Watch

Certification timelines will determine how long Energy Markets price sustained disruption. If a provisional agreement emerges this week, the certification window could extend 2-4 weeks beyond signature — sufficient time for oil price volatility to spike if Iran signals non-compliance or if U.S. intelligence assesses inadequate nuclear commitments.

Congressional oversight will shape the certification process itself. The Congressional Research Service estimated the blockade’s operational cost at $29 billion, with legislative requirements for sanctions architecture review. Republican critics have already signalled intent to scrutinise any framework allowing Iran near-term economic relief without irreversible nuclear rollback.

Tehran’s calculus turns on whether it can sustain $500 million daily losses through certification, or whether domestic economic pressure forces acceptance of terms that defer Strait reopening until Washington validates compliance. The 240 ships queued outside Iranian waters represent both immediate revenue loss and a visible measure of Iran’s isolation — pressure Trump appears willing to maintain until he secures nuclear concessions on U.S. terms.