Iran’s Leaders Can Afford to Be Patient
By Jennifer Kavanagh
Ms. Kavanagh is director of military analysis at Defense Priorities.
It shouldn’t have been surprising when President Trump announced on April 12that the United States would begin a blockade of Iranian ports to force Tehran to accept a peace deal.
Mr. Trump prides himself on being unpredictable. But he is a creature of habit, and blockades have quickly emerged as one of his preferred military tactics since his return to the White House. He has already used them against Venezuela and Cuba. Now his administration has expanded the Iran embargo, and started to seize Iran-linked ships on the high seas.
Iran’s grip on the Strait of Hormuz was not the reason the United States started this war. Before the conflict, traffic passed freely through the narrow waterway. But Tehran’s effective closure of the strait since the United States and Israel attacked two months ago has emerged as the war’s most bedeviling problem and one Mr. Trump is desperate to fix. He hopes that by instituting a blockade of his own, he can choke Iran’s economy and force the country’s leaders to reopen the strait and accept Washington’s terms of surrender.
This is unlikely to work for the same reasons the United States finds itself facing strategic defeat by a weaker adversary: a mismatch of stakes and time horizons. While Iran has gained the upper hand in this conflict by extending and surviving what it considers an existential war, Mr. Trump wants a fast and decisive victory, something a blockade cannot deliver. A blockade may impose costs on Iran’s economy and population, but it will not deal the quick knockout blow the Trump administration seeks.
Blockades are designed to work slowly, with pressure accumulating over time. At the beginning of the American Civil War, for example, President Abraham Lincoln ordered a blockade of ports across the Confederacy, targeting some 3,500 miles of coastline. It had the desired effect, eventually cutting Southern cotton exports by as much as 90 percent and severely damaging the Southern economy. But it did not result in a rapid end to the war: Fighting between North and South continued for four years.
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A similar story played out during the British naval blockade of Germany in World War I. Instituted almost immediately after the war began in 1914, it aimed to limit Germany’s access to essentials like food and medicine and matériel that might support the war effort. The blockade imposed severe hardship on the German people, contributing to hundreds of thousands of civilian deaths, and hampered military operations. But Germany did not immediately surrender. The war endured until the end of 1918.
That blockades often fail to quickly change an adversary’s behavior is something Mr. Trump and his advisers should know. Earlier this year, the United States started interdicting oil shipments to Cuba in an effort to force Havana to make political and economic concessions. The island is now on the brink of humanitarian collapse, but the Cuban regime has yet to yield. The U.S. blockade of Venezuela’s oil exports was similarly ineffective: Mr. Trump announced it in December 2025, part of a monthslong pressure campaign to force President Nicolás Maduro to step down. When a few weeks of blockadefailed to elicit any compromise, Mr. Trump had to escalate further, seizing Mr. Maduro and his wife in a dangerous military raid.
Iran may prove even more resilient. The blockade has reduced the country’s oil revenues to a fraction of their prewar levels, but it is likely to be some time before the consequences become untenable for Iran’s regime. In the near term, Tehran will continue to receive oil revenue from shipments that left its ports weeks ago, and at least 34 tankers with links to Iran appear to have slipped through the blockade. These and any future successful exports can be sold at higher prices, which may continue to rise as the war drags on.
To prevent this, the administration has said the U.S. military will pursue any ship helping Iran, anywhere in the world, a move that is of ambiguous legality under international law. To meet the legal standard, any blockade must be deemed “effective,” meaning it is carried out with enough military power to be consistently and impartially enforced; have clearly defined geographic limits; and include provisions for humanitarian relief. The expanded U.S. blockade meets none of these requirements. It has no geographic boundaries or humanitarian provisions, and the U.S. Navy’s limited capacity to interdict container ships and tankers means it will have to choose which cargoes to intercept or focus on specific regions. It cannot, therefore, be “effective.” In the end, most Iranian oil shipments that are already at sea will almost certainly make it to their destinations.
At home, Iran has other ways to mitigate the effects of the blockade. Recent estimates suggest Iran has about 90 million barrels of available oil storage capacity, enough for at least two months of production, before it must make production cuts that risk permanent damage to its oil infrastructure. Tehran also has reserves of food and other essentials, and land-based trade routes that it can fall back on if needed for imports of some commodities and even some oil exports. Iran can likely endure the U.S. blockade for months without facing economic collapse. Even then, its leaders might choose to fight on rather than agree to American terms they perceive as a compromise of Iranian sovereignty.
For Mr. Trump, this timeline is likely to be unacceptable. His impatience with the war is evident in his increasingly erratic Truth Social posts and near-constant assertions that the war is already over.
His sense of urgency is understandable. Not only is the war deeply unpopular in the United States, but its effects on the American and global economies are real — and likely to grow. The longer the impasse lasts, the more severe fuel and fertilizer shortages will become across East Asia and Europe, and the more Gulf state oil exporters will suffer. A prolonged blockade will also push global oil prices higher, increasing U.S. inflation and torpedoing Mr. Trump’s affordability pitch in the upcoming midterm elections.
Instead of stripping Iran of its most important source of leverage — control of the Strait of Hormuz — Mr. Trump’s blockade may play into the Islamic republic’s hands. The blockade harms Iran’s economic future, but may lead to a longer, costlier war for the United States, severe and lasting damage to U.S. and global markets and further domestic political damage for Mr. Trump.
In a test of wills, Tehran has the advantage and a higher pain tolerance. With their survival on the line, Iran’s leaders can afford to be patient.“
