15JUN

Two US carriers stay, blockade runs on

3 min read

11:40UTC

The USS Abraham Lincoln and the USS George H.W. Bush remained on station in the Gulf as of 18 June, the blockade still redirecting vessels, despite the memorandum's clause that it be removed immediately.

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Key takeaway

Two carriers on station are the proof the order to lift the blockade never reached the fleet.

Two US carrier strike groups, built around the USS Abraham Lincoln and the USS George H.W. Bush, remained on station in the Gulf region as of 17-18 June⁠¹. CENTCOM (US Central Command), the US military command for the Middle East, has issued no drawdown order, and the naval blockade continues to redirect vessels, despite the Islamabad Memorandum of Understanding (MoU) clause that the blockade be "removed immediately."

The blockade is the apparatus that has throttled Iranian seaborne trade through the war, turning the strait into a corridor ships transit only on US sufferance. Trump signed the MOU and ordered the blockade lifted on 16 June, but CENTCOM kept it running pending a signed instrument it has not received. The carriers on station are the physical evidence that the order has not reached the water.

The shipping industry reads operations, not press releases. Insurers, mine-clearance crews and tanker owners need an on-water change before commercial transits resume; a memorandum does not move a hull. Hormuz logged zero new tanker transits the day after Trump signed. The Geneva signing ceremony was scrapped, and Baghaei confirmed the text was finalised electronically, the presidents' signatures applied digitally rather than at any podium.

Deep Analysis

In plain English

Think of the naval blockade as a lock on a gate that is run by one department and the key as a different document held by another department. When the US President signed the Islamabad MoU, he was handing over a promise to unlock the gate. But the military commanders operating the lock need a separate written order from the Defence Department before they can actually turn the key. As of 18 June, that order had not arrived. So both aircraft carriers, the Abraham Lincoln and the George H.W. Bush, stayed in position, redirecting ships just as before. The gate remained locked. Separately, the sea still has live floating mines in it. Even if the lock were opened, no commercial ship would sail through a minefield without a guarantee that the mines had been removed.

Deep Analysis

Root Causes

The blockade-stays problem has a structural cause independent of politics: the CENTCOM enforcement mechanism runs on a separate chain of command from the diplomatic track that produced the MOU. Trump signed the MOU as the US executive; the blockade is operationalised by CENTCOM via the Secretary of Defense chain. Without a National Security Council decision memo, a SecDef order, and a CENTCOM operational directive, the blockade runs by default.

Mine-clearance progress also blocks the blockade lift. Hormuz was still seeded with active mines on 18 June. BIMCO and the International Chamber of Shipping have stated publicly that commercial vessels will not transit an uncleared minefield regardless of what a ceasefire agreement says. The operational prerequisite for the blockade lift, cleared lanes, does not yet exist.

What could happen next?

Risk
An incident between an on-station carrier and an IRGC vessel, as happened on 15 June with the 'last warning' radio transmission, could escalate to an exchange of fire that voids the MOU before the 19 June ceremony.
Immediate · Reported
Consequence
The carrier stay gives Iran a public talking point: the US blockade continues despite the signed MOU, symmetrically matching Iran's own non-compliance on Lebanon.
Short term · Assessed
Precedent
If the blockade does not begin to lift within seven days of signing, insurers will treat the MOU as a rhetorical instrument rather than an operational change, maintaining war-risk exclusions and keeping effective transit near zero.
Short term · Assessed

Source Landscape

This story draws on mixed-leaning sources from Qatar and United States

Qatar

United States

LeftRight

Primary parallel: After the 1973 Paris Peace Accords ending the Vietnam War, US naval forces in the Gulf of Tonkin did not withdraw immediately on signature. CINCPAC kept carrier groups on station for 27 days pending a formal withdrawal schedule issued by the Joint Chiefs. The operational gap between a signed agreement and force drawdown is a documented feature of US military doctrine, not an anomaly. The Islamabad MoU's 'immediately' language conflicts with this doctrine directly.

Counter-parallel: After the 1994 Agreed Framework with North Korea, US naval assets in Korean waters remained unchanged because the agreement was explicitly prospective: it set conditions for a future state, not immediate compliance. The Islamabad MoU's language is more like the Paris Accords (immediate action required) than the Agreed Framework (conditions for future compliance), which makes the operational gap more consequential.

Consensus view: Naval force posture does not change on diplomatic signal; it changes on a signed operational order. CENTCOM cannot legally begin a drawdown without a written instrument from the Secretary of Defense or the Commander in Chief.

Trump's verbal instruction to reopen the strait does not constitute that instrument. The War Zone reported on 15 June that the drawdown details remained 'murky' even after the digital signing, confirming the carriers on station are following standard doctrine, not defying orders.

Counter-view: The carrier stay may also reflect a deliberate Pentagon hedging calculation: keeping force posture in place preserves military leverage during the 60-day nuclear negotiating window, regardless of what the MOU says about immediate blockade removal. Under this reading CENTCOM is not waiting for paperwork but holding position by institutional design, with The Administration's tacit approval.

Key tension: Whether the carrier stay represents bureaucratic compliance with normal procedure (waiting for a signed order) or reflects the Pentagon's own assessment that maintaining forward presence during the 60-day nuclear negotiation window serves US interests better than a rapid withdrawal.

Sources:Al Jazeera·The War Zone

Mentions:CENTCOM (US Central Command) →Esmaeil Baqaei →Islamabad Memorandum of Understanding →Vietnam →Islamabad →Geneva →The War Zone →Paris →North Korea →Pentagon →USS Abraham Lincoln →USS George H.W. Bush →Strait of Hormuz →

First Reported In

Update #131 · Iran deal's first death tests the text

Al Jazeera· 18 Jun 2026

Read original →

Causes and effects

Caused by

Trump signed Hormuz open; war ran on

Trump signed the MOU and ordered the blockade lifted but CENTCOM received no signed drawdown instrument, leaving the carriers on station.

Occurred 16 Jun 2026

Read story →

This Event

Two US carriers stay, blockade runs on

Insurers and shippers need an on-water change, not a memorandum, before tankers move.

Led to

Oil prices a Hormuz reopening that has not happened

Brent pricing a blockade lift that two on-station carrier strike groups and no CENTCOM drawdown order refute.

Occurred 18 Jun 2026

Read story →

The carriers that did not leave

The USS Abraham Lincoln and George H.W. Bush holding station on 18 June (event 8) continued the posture already established with still no drawdown order issued.

Occurred 18 Jun 2026

Read story →

Different Perspectives

United States (Joint Maritime Information Center)

The JMIC, the US-led naval reporting cell, rated the Hormuz threat "severe" in its 25 October advisory, as reported by gCaptain, and warned of possible renewed mining. Eight days earlier it found no substantiation for the Guards' mine claims, while US-facilitated transits ran at about 34 a day.

United Kingdom (CPS and Counter Terrorism Policing)

The CPS charged two men under the National Security Act 2023 over the RAF Fairford incident, and Counter Terrorism Policing said it believes the foreign intelligence service involved is Iran's, LBC reported. The case now runs through the courts; both men are charged, not convicted.

Aden and Yemen's recognised government

The Houthis told people to leave Aden airport, in the government-held south, before a missile fell there on 28 October, AFP reported, and police reported a second attack that afternoon. The fight between Riyadh and the Houthis is landing on the south's main civilian airport.

Qatar (mediators)

Qatar-led mediators put new terms to Iran this week, which an Iranian official called "ideas, not a proposal". Riyadh framed the Tehran meeting as support for Qatari and Pakistani mediation, keeping Doha at the centre of the indirect channel.

Korea Shipowners' Association

The association said the ships Iran listed were sub-chartered to an overseas oil company, not owned by Sinokor, carried no South Korean crew, and that Sinokor was unaware of the warning. South Korea's shipowners are contesting whose vessels the notice covers before it takes effect.

Kuwait (foreign ministry)

Kuwait summoned Iran's ambassador, Mohammad Toutounji, and handed him a protest note over the embassy's denial that its citizen took part in the alleged plot against Interior Minister Fahad Al-Yousef. Kuwait is answering through its courts and a diplomatic protest, citing international law and the UN Charter.

Written with AI from Lowdown's published reporting. Not individually reviewed by an editor. Editorial standards.