Dr John Hemmings
There is a bit of a debate about whether or not Donald Trump’s naval blockade of Iran is working. The Wall Street Journal’s editorial board argued this on April 13th, noting that US Central Command (CENTCOM) had declared that no Iranian ships had made it past their blockade that first day. According to Miad Maleki, a senior fellow at of the Foundation for the Defense of Democracies and former US Treasury official, the blockade could wipe out $435 million in daily economic activity. According to Denis Ross, a former US official, Trump’s pressure on Iranian oil puts “greater pressure on Iran” and “greater pressure on China to pressure Iran”. According to some accounts Iran is suffering $435 million in daily economic damage, or roughly $13 billion per month. By this argument, then it seem that Trump’s blockade is working.
But there are three huge holes in this argument and yes, they are holes that a China-bound tanker might sail through: first, it’s not clear the blockade is actually achieving the intended objective of stopping Iran from exporting crude to China. According to analysis of ship-tracking data and Lloyd’s List intelligence, between 26 and 34 Iranian oil tankers have slipped through the blockade since the 13th, with at least five Iranian vessels having been identified, and having now reached the Indian coastline. We know from the disappearance and then reappearance of their transmitters that the vessels – probably part of the “shadow fleet” Iran uses for just this purpose – turned off their automatic identification system (AIS) or broadcast false positions, in what is called spoofing.
The second weakness in this argument is that while 90% of Iranian oil is bound for China, Trump has lost valuable leverage the longer the conflict has continued. This is partly because US Gulf State, Indian, and European allies are also suffering from the closure of the Strait and are building pressure on Washington and partly because of the balancing act that Trump is attempting vis a vis Beijing. Ever since the White House agreed to a new date of May 15th for the Xi-Trump summit, it is clear that CENTCOM has orders to let some Chinese-bound vessels through. The red line for Trump seems to be the shipment of weapons systems to Iran, but other than that, it is clear that the President does not want to damage relations prior to the summit. Beijing has directly criticized the blockade, calling it “dangerous and irresponsible act”.
The third weakness lays with the long line of China-bound Iranian vessels already in transit – which left before the blockade was declared. As of mid-April, there are currently 157.7 million to 160 million barrels of Iranian oil currently on tankers at sea, according to Windward, a maritime intelligence firm, with nearly 98% of them destined for China. This means that both Beijing and Tehran have a long “buffer” of oil supplies for at least the next 120 days. So despite the fact that CENTCOM has reported having halted or intercepted 27 vessels as of late April, it is clear that this is an imperfect blockade, both politically and militarily. The US-China relationship is playing a factor and once again Beijing is providing a lifeline for an ally under the American gun.
While every one of these concerns is relevant, and while each point to the weakness of the blockade, the overall approach misses the point. The primary strength in the US position is less about stopping every ship and more about piling on layers of pressure. Trump never uses one method to pressure his opponents, after all. His tactics usually involve adding pressure point after pressure point. Think of the blockade as merely another element on an escalation ladder. The US could take Kharg island, for example. The taking or destruction of Kharg would destroy the terminal through which 90% of Iranian oil exports pass, bringing to an immediate end all Iranian oil exports. Trump has also threatened to strike Iranian critical national infrastructure – bridges, power plants, desalination plants – crippling the economy for years to come.
The military is not Trump’s only tool on the escalatory ladder. Sanctions have been increased by the US Treasury under Operation “Economic Fury”. Cutting an enemy off from international markets remains one of the US’ greatest weapons. Trump has shown that he’s willing to add secondary trade tariffs to the list – hitting out at third-party nations that support Tehran. Despite the White House’s orders to minimize friction with China, the Treasury Department sanctioned the Shanghai Xuanrun Shipping Co for facilitating Iranian oil transportation in the face of the blockade on April 15th. On the 16th, US Treasury Secretary Scott Bessent threated a number of Chinese financial institutions that continued to facilitate trade with Iran. The warnings also involved two major Chinese banks who regularly handle Iranian currency exchanges.
So the question is not whether or not the blockade is working, but to what extent it contributes to Trump’s spectrum of pressure points.
