Donald Trump was in a Miami arena on Saturday night watching a live Ultimate Fighting Championship bout as his vice-president, JD Vance, announced there was no peace deal with Iran after marathon talks in Pakistan.
The world therefore had to wait until Sunday morning to hear the US president’s response – a naval blockade of the Strait of Hormuz, potentially seizing any vessels paying tolls to Tehran.
It was Trump’s latest attempt to change the dynamic of the US-Israeli war against Iran, which he launched in late February but is struggling to exit, having underestimated the Islamic Republic’s ability to choke off energy trade through the critical waterway.
On its surface, the naval embargo is intended to shrink Iran’s capacity to fund its defence by limiting the revenue it generates from oil exports. But such an operation risks further destabilising global energy markets and triggering a new surge in oil prices. It also jeopardises a fragile two-week ceasefire agreed by the US and Iran last Tuesday.
“Closing the strait entirely will spike oil prices even more than they did before, and put more pressure on the US from the international community,” said Jennifer Kavanagh, director of military analysis at Defense Priorities, a Washington think tank.
“It definitely shows how frustrated and at the end of his options the president feels,” she added.
Trump’s order of an embargo on the strait reflects his hope that he can apply to Iran the model of his intervention in Venezuela, when the US seized then-president Nicolás Maduro in a military operation after a naval blockade of the Latin American nation.
“We’re putting on a complete blockade. We’re not going to let Iran make money on selling oil to people that they like, and not people that they don’t like, or whatever it is,” Trump told Fox News on Sunday.
“You saw what we did with Venezuela. It’ll be something very similar to that, but at a higher level.”
Trump aides say the imposition of a naval embargo – set to begin at 10am eastern US time (3pm Irish time) on Monday – was the consequence of Iranian intransigence in negotiations between the two countries since the ceasefire, and designed to put additional pressure on Tehran.
Specifically, free passage through the Strait of Hormuz was one of a series of red-line demands that Iran failed to agree to in talks led by Vance in Pakistan on Saturday, a US official said. Others include the dismantling of Tehran’s uranium enrichment facilities – which the US bombed last June – the retrieval of its enriched uranium stockpiles, and the ending of Iran’s funding of regional proxy groups.
After devising the blockade with Trump and his team, Vance is hopeful Iran will be more willing to accept a deal meeting US demands, the US official said.
But the Islamic regime has repeatedly shown it is not willing to capitulate to pressure. It believes it has the upper hand in the conflict, with the strait its main point of leverage.
Iranian foreign minister Abbas Araghchi blamed the Trump administration for the lack of progress at the talks in Islamabad, which were the highest-level negotiations between the US and Iran since the 1979 Islamic Revolution.
“In intensive talks at highest level in 47 years, Iran engaged with US in good faith to end war,” Araghchi, who was part of the Iranian delegation, said on X. “But when just inches away from ‘Islamabad MoU’, we encountered maximalism, shifting goalposts, and blockade. Zero lessons earned.”
Some analysts supported the proposed blockade. “It stops Iran’s exports, its revenues, is a counterpoint to their closing the Straits,” Dennis Ross, the former senior US diplomat and Middle East negotiator, wrote on X.
“They may attack Gulf oil facilities but it puts greater pressure on Iran. It also puts great pressure on China to pressure Iran,” he added.
“The ‘Open for All or Closed to All’ policy could rally the world as it reflects a commitment to keeping an international waterway open to nearly everyone’s benefit. It would not increase the damage and destruction of the war,” added Richard Haass, another former US diplomat, writing in his Substack.
But others were sceptical, such as Vali Nasr, a former US official and a professor at Johns Hopkins University. He said Trump’s threat to blockade the strait would not concern the Islamic republic in the short term, with Tehran calculating that a closure puts more pressure on the global economy than on Iran.
“This is fine by the Iranians, it prolongs the chokehold on the global economy,” he said. “And the Iranians could shut down [the] Bab el-Mandeb [a chokepoint off the coast of Yemen] and then the US will have to deal with that.”
>From the war’s outset, Iran has made clear that one of its prime objectives, as it faces what it considers an existential battle for its survival, has been to raise the costs of the conflict for the US, its allies and the global economy.
“I don’t understand how blockading the strait is going to somehow push the Iranians into opening it. I don’t get the connection there,” Mark Warner, the Democratic senator from Virginia, told CNN on Sunday.
Esfandyar Batmanghelidj, chief executive of the UK-based Bourse and Bazaar Foundation think tank, said Iran had already blockaded itself with limited access to oil revenues.
“A US blockade might squeeze Iranian oil out of the market, but the impact on the state budget will be secondary and will anyway pale in comparison to the costs that Iran was willing to sustain from air strikes. If this is a tactic to add pressure on Iran, it is an odd one,” Batmanghelidj said.
The US Central Command said in a statement that the blockade would be “enforced impartially against vessels of all nations entering or departing Iranian ports and coastal areas, including all Iranian ports on the Arabian Gulf and Gulf of Oman”.
Analysts have repeatedly cautioned against making comparisons to Maduro’s regime in Venezuela, pointing out that the Islamic Republic has over nearly half a century established an entrenched bureaucracy and spent decades preparing for the type of asymmetrical warfare it is fighting, led by the ideologically motivated Revolutionary Guards.
Whereas in Venezuela, Trump was able to find a compliant successor to Maduro in Delcy Rodríguez, the new president, the remaining regime leaders in Iran after the killing of Ayatollah Ali Khamenei – who was replaced as supreme leader by his son Mojtaba – and other senior figures have not been willing to cave in to US demands.
Trump’s naval blockade represents an abrupt shift from Washington’s strategy of allowing Iran to continue exporting oil as it has sought to calm energy markets. It has also tried to compensate for the production losses its Gulf neighbours have suffered as a result of the strait’s closure and Iranian attacks on their oil and gas facilities.
The strait is important for Iran’s exports and imports. But it has alternatives to bring in food imports and other goods, as it shares borders with 15 countries, including land routes to Iraq and Turkey in the west, central Asian states and Russia in the north, and Afghanistan and Pakistan in the east.
Kavanagh said a US naval blockade of the Strait of Hormuz would also pose some operational challenges and dilemmas that did not exist during the action against energy shipments to and from Venezuela.
“Let’s say that it’s a Gulf state or a French ship that’s going through and they did pay the toll,” she said. “What’s the US going to do? Seize an allied tanker? And let’s then, say that it’s a Chinese ship that paid the toll. Are we going to seize a Chinese tanker? And what are the Chinese going to do?” – Copyright The Financial Times Limited 2026