WASHINGTON, July 13 — The technical reality of Donald Trump’s Iran policy is, as ever, a matter of pressure gradients and volumetric flow. Under the hood, the mechanism is identical to the one he first deployed as the 45th President: economic strangulation via the Strait of Hormuz. On March 20, 2025, Trump announced a 20 percent toll on all cargo transiting the chokepoint, effectively restarting the naval blockade that defined his first-term ‘maximum pressure’ campaign.
That original campaign, launched after Trump withdrew the United States from the Joint Comprehensive Plan of Action on May 8, 2018, had a clear technical objective: reduce Iran’s oil exports to zero. The president called the JCPOA “a horrible one-sided deal” and proceeded to reimpose sanctions in two distinct phases.
The first, in August 2018, targeted financial transactions and the automotive sector. The second, in November 2018, went after the real prize: oil exports and shipping. The detail that matters is the export curve.
In 2018, Iran was shipping 2.5 million barrels per day. By 2020, that figure had collapsed to about 0.4 million.
The mechanism was straightforward — any buyer of Iranian crude risked being cut off from the US financial system. Trump also designated Iran’s Islamic Revolutionary Guard Corps as a terrorist organization on April 8, 2019, adding a legal layer to the economic pressure.
Blockade 2.0
The 2025 Strait toll is a refinement of the same approach. Rather than relying solely on secondary sanctions to deter buyers, the administration now imposes a direct cost on the transit itself. The 20 percent levy applies to all cargo passing through the Strait of Hormuz, the narrow waterway through which roughly a fifth of the world’s petroleum transits.
The effect is to make Iranian crude more expensive to ship, even if a buyer is willing to risk US sanctions. The wry observation here is that the Abraham Accords, brokered by the Trump administration in 2020, complicate the regional picture.
Those agreements normalised relations between Israel and the UAE, Bahrain, Sudan, and Morocco. They did not, however, address the Strait of Hormuz calculus. The Gulf Arab states that signed the accords remain dependent on the same waterway for their own oil exports, and a 20 percent toll applies to them as well.
The IRGC designation
The April 2019 designation of the IRGC as a terrorist organisation was a first — no previous US administration had taken that step. It gave the Treasury Department additional legal authority to target entities doing business with the Guard, which controls large portions of Iran’s economy, including its oil and gas sector. The designation remains in effect under Trump’s current term, providing the legal infrastructure for the Strait toll enforcement.
What to watch next is the actual flow rate. The 2020 low of about 0.4 million barrels per day was achieved through diplomatic pressure on buyers like China, India, and Turkey.
The 2025 toll adds a mechanical constraint — ships must either pay, risk interdiction, or find alternative routes. The technical reality is that there are no viable alternatives for bulk crude transit out of the Persian Gulf. The Strait of Hormuz is the only deep-water exit.
