A that President Donald Trump said began Monday could further disrupt oil prices, has spurred questions about international law and leaves doubts about whether the pressure tactic will force Tehran to reopen the vital Strait of Hormuz.
Trump threatened to impose the blockade after talks to further a fragile ceasefire ended without a deal this past weekend. Iran had previously halted nearly all tanker traffic through the key waterway, allowing only some ships perceived as friendly to pass while .
Enforcing the blockade is likely to demand significant resources from the U.S. Navy and could prompt concerns about military force and international law, experts say. Supply chain analysts, meanwhile, stress that the restrictions could undermine the flow of oil, fertilizer, food and other goods to consumers already facing higher prices.
How the US could enforce a blockade of Iranian ports
Successfully enforcing the blockade will require a sustained commitment of U.S. Navy ships and personnel, as well as clear guidance from the Trump administration and the Navy鈥檚 legal department, experts say.
American military officials have offered few details. The U.S. has 16 , a defense official said. A second defense official said no warships are in the Persian Gulf 鈥� the body of water that forms most of Iran鈥檚 coastline. Both spoke on condition of anonymity to discuss sensitive military operations.
The second official pointed to a notice to mariners as a more accurate representation of the military鈥檚 plans. It says access to Iranian ports is being restricted, but the ways these measures 鈥渨ill be applied in practice … are in development.鈥�
The biggest challenge will be the enormous volume of shipping traffic that usually transits the Strait of Hormuz, where nearly 20% of the world’s traded oil passes in peacetime. A considerable number of ships may be needed to enforce the restrictions, said Sidharth Kaushal, a naval power expert at the Royal United Services Institute, a defense and security think tank in London.
鈥淎 lot depends on the early days of the blockade, how many vessels the Americans can seize, how much they can convince vessels attempting to slip through a cordon that they鈥檙e likely to be seized,鈥� Kaushal said. 鈥淏ut in all likelihood, I鈥檇 say it will prove difficult for the U.S. to enforce.鈥�
The strait鈥檚 narrow confines at least will make the geographic area of concern a limited one, said Todd Huntley, director of Georgetown University Law Center鈥檚 National Security Law Program. Still, the amount of traffic that goes through 鈥渋s going to be a challenge,鈥� he said.
The U.S. may have to consider whether to allow humanitarian aid to reach Iranian ports, Huntley said, a decision that could determine the blockade鈥檚 legality under international law. International rules also require that any nation enforcing a blockade do so impartially, after issuing an advisory to mariners.
鈥淗ow it is carried out will determine whether it is lawful or not,鈥� said Huntley, a retired Navy captain and judge advocate general. 鈥淵ou can鈥檛 enact a blockade with the goal of starving the civilian population. Even the DOD law of war manual states that neutral vessels carrying relief supplies should be allowed to pass.鈥�
Few merchant vessels are likely to try to evade a blockade, said Raul Pedrozo, professor of international law at the Naval War College and a retired Navy captain and JAG officer. They won鈥檛 want to take their chances against the U.S. Navy, he said.
鈥淭hey see a warship, and they鈥檙e going to heave to,鈥� Pedrozo said.
Naval blockades aren’t a fix-all but can be a tool
Blockades historically haven鈥檛 been enough on their own but have been used to exert pressure on other countries and their economies during conflicts, experts say.
鈥淭here are always ways to economize, import, substitute, or just give up on certain things that you can no longer build for want of foreign inputs,” Kaushal said. “It can make things a lot harder in a lot of ways, but it doesn鈥檛 necessarily achieve decisive outcomes.鈥�
A blockade alone can鈥檛 sever Iran鈥檚 economic ties with trading partners, including China and Russia, or cut off access to the Caspian Sea or Central Asia.
The blockade also risks an Iranian response that could reignite the conflict, said Farzin Nadimi, who specializes in Iran and the Persian Gulf at the Washington Institute for Near East Policy.
Iran could deploy naval mines, small fast-attack boats and missiles against shipping in response, further disrupting the global economy.
鈥淭he U.S. wants this to be a short and sweet operation. I don鈥檛 think that it can be,鈥� Nadimi said.
Trump said Iran has some 鈥渇ast attack ships鈥� remaining and Tehran that any of them coming 鈥渁nywhere close鈥� to the U.S. blockade would be destroyed by a 鈥渜uick and brutal鈥� strike. Iran responded with its own threats on ports in the Persian Gulf and Gulf of Oman.
Oil prices could keep rising
With fears of attacks, experts say most ships won’t want to take the risk. The waterway could effectively stay shut 鈥� and prices, particularly for oil and gasoline, could rise even more.
鈥淭he problem with a two-side blockade is that you know it鈥檚 going to take much longer for the strait to open up and for some kind of agreement to come about 鈥� and that鈥檚 what’s going to send these prices further skyrocketing,鈥� said Vidya Mani, a visiting associate professor at Cornell University whose research focuses on supply chains.
Analysts warn that the longer the waterway is closed, the worse prices could get. Oil has swung on markets’ quick reactions to announcements from Trump and others about the fate of the war, but they remain steep overall, with crude , up from roughly $70 before the war.
Households and businesses are paying the consequences 鈥� particularly in Asia, where countries on fuel imports from the Middle East. But oil is a globally traded commodity, and consumers worldwide are feeling a pinch in their wallets.
American drivers, for example, have seen gas prices spike to an average of more than $4.12 a gallon 鈥� up from $2.98 before the war.
Global supply chains also could see further disruptions
The blockade also would hurt the transportation of food and fertilizer, said Patrick Penfield, professor of supply chain practice at Syracuse University. He said the United Arab Emirates, Qatar, Bahrain and others could especially see 鈥渄ramatic food price increases,鈥� as supplies will have to be flown in.
Some comes through the strait, potentially harming farmers and as a result worsening hunger worldwide.
鈥淣ow you鈥檙e talking about impacting the global harvest,鈥� Penfield said. Between these disruptions and oil shocks, he noted that such chaos and uncertainty 鈥渂leeds out throughout the whole world.鈥�
Mani said chemicals to make basic supplies such as paint and metal such as aluminum also pass through the region and would see additional disruptions. She pointed to price pressures even before the U.S. and Israel launched their war against Iran 鈥� including new tariffs from Trump, supply chain problems from the COVID-19 pandemic and other geopolitical conflicts.
鈥淲e just have to be prepared for constant higher prices, irrespective of how this blockade turns out,鈥� she said. 鈥淓ach crisis has a lingering effect on the next one.鈥�
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Associated Press writers Konstantin Toropin in Washington and Mae Anderson in New York contributed to this report.
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