Geography, Munitions, and Oil: Three Issues Pointing Toward a Long Iran War.
When desperation, anger, and leverage coincide, wars burn for a long time.
The US appears presently unable to re-open the Strait of Hormuz at an acceptable level of risk and casualties and thus now seeks to share the blood and burden with a broader group of countries.
This suggests the Strait of Hormuz situation is rapidly becoming a supersized and very high-stakes version of the maritime transit problems the Houthis caused on the Red Sea. One key implication is that while U.S. officials publicly communicate a sense of control over the time remaining in this war, Iran is in fact the actor that will determine when and how it ends.
Item #1: Oil Inventories
Operations to re-open the Strait to unrestricted traffic face intense time pressure. The current net deficit of crude oil exports from the Gulf is approximately 10 million bpd (rising to 11.5 million bpd if Fujairah is shut down). That is about 10-to-12% of global supply. Oil inventories are not meant to compensate for such large volumes for weeks on end.
As of January 2026, IEA data showed observed global oil inventories of 8.2 billion barrels. Of this, 4.1 billion barrels were in the OECD countries, 1.2 billion barrels were in China, 2.05 billion barrels were aboard oil tankers headed to customers, and about 0.9 billion barrels were held in non-OECD countries.
Now that IEA member countries have committed to a collective release of 400 million barrels, global observed inventories likely remain in the 7.8-billion-barrel range. If we take out the oil already moving in tankers and just focus on the “delivery taken by customer oil” in tanks and caverns at refineries, ports, and tank farms around the world, that leaves approximately 5.7 billion barrels.
A week of the Strait closed at today’s loss rate thus effectively removes about 1.25% of this global cushion. Put differently, the first 10 weeks of stock drawdowns at today’s rate means a day of forward coverage is lost each week. Thereafter, each week sees 2 days of forward coverage lost.
Higher prices will, over time, destroy some oil demand and extend inventory life. But that reaction takes time. Also, oil demand destruction is a bloodless way of saying “economic activity slows”—a reaction with enormous political consequences in a US midterm election year.
Accordingly, the impact of the denominator shrinking faster than oil demand likely means that as levels in tanks and storage caverns decline, the upward pressure on oil prices will likely increase at a non-linear, fear-driven rate: in other words, a price rise of 5% due to news today could be a 10% move if similar news hit the airwaves a week from now. Indeed, futures markets are pricing near-$100 crude oil through June, further suggesting markets see more sustained risk than the White House is publicly communicating.
All these dynamics reinforce Iran’s leverage each day the shutdown continues. They also commensurately increase the pressure on the US to either escalate significantly—perhaps by striking Kharg Island oil facilities or seizing shadow tankers carrying Iranian oil to China—or else accept a new, strategically unfavorable status quo.
Item #2: Geography
Geography favors Iran. No amount of US air supremacy changes the fact that Iran is a massive country and that it has the southern reaches of the Zagros Mountains in the vicinity of the Strait of Hormuz, offering myriad opportunities to dig tunnels to hide mobile anti-ship cruise missile systems as well as short range ballistic missiles.
Iran’s geographic command of the Strait and its approaches also provides numerous opportunities to lay sea mines, including from smaller speedboats and potentially even towing them into the channel with drone boats and unmanned submersible vehicles.
Missiles, drones, and mines underpin navies’ hesitance to take on escort missions through the Strait right now. An Iranian Noor anti-ship cruise missile launched from a mountain tunnel 40 miles inland and travelling at 600 mph would cover the distance in about 5 minutes.
A missile launched from closer in would leave even less time to detect and react. If such munitions hit a ship, they pack combined kinetic and explosive energy on par with a World War II kamikaze aircraft impact.
The results are devastating, as the US Navy experienced in 1987 when a pair of Exocet anti-ship missiles fired by an Iraqi aircraft struck and nearly sank the USS Stark in the Persian Gulf. The strike killed 37 sailors. For a sense of the destruction caused by the missiles, see the sailor standing near the center of the picture below.
A. Geography Amplifies the Task Ahead, Air Power May Not Be Enough
Iran likely still has hundreds of missiles capable of inflicting this level of damage. Whether by missile, mine, drone boat, or other means, Iran has many ways to damage warships sufficiently that even if they remain afloat, repairs could take 12-18 months.
In addition to the immediate human consequences for those on board, the strategic consequences of losing ships badly needed for deterrence in Asia would be enormous. North Korea tests nuclear-capable rockets when the US moves air defense from South Korea to the Middle East. Imagine what China might do vis-a-vis Taiwan if Hormuz escort losses compromise US naval power?
Stopping such attacks with air power alone may not be feasible. The White House decision to dispatch the 31st Marine Expeditionary Unit from East Asia to the Middle East brings a range of potential raid and assault capabilities that could conceivably be used to seize a buffer zone near the Strait.
Temporarily occupying a 20-mile-deep buffer zone for 50 miles on either side of the Strait’s geographic center near Bandar Abbas would entail needing to control an area about the size of Delaware. This task area would likely be too large for the roughly 2,500 Marines aboard the task force now heading to the Middle East.
Each operational zone is unique, but for perspective, the evacuation of people from Afghanistan in August 2021 required more than 2,000 Marines at the Hamid Karzai International Airport and city of Kabul alone. This was a far smaller area than what might be contemplated in Iran, whose military forces could still bring far more firepower to bear on an assault force than the Taliban could have in Afghanistan.
Item #3: Munitions
Iran’s knowledge that control of the Strait is now its strongest single strategic card means that it will not relinquish control easily. That in turn means the US is going to have to reestablish free transit using sheer firepower.
American forces face a heavy burden. If Iran can launch even a few munitions per day, either ships will remain hesitant to sail through the Strait or else, they will seek Iranian permission to transit, thus solidifying a reality of de facto Iranian control over the Strait that Washington will almost certainly find unacceptable.
Past combat operations’ munitions use data can offer glimmers of insight into what current campaigns might require. The chart below plots monthly aerial weapons releases in the Central Command area of responsibility, primarily Afghanistan, Iraq, and Syria.
The core 3-year period of the anti-ISIS fight saw the use of approximately 100,000 munitions, many of the direct attack bombs. The analogy is inherently imperfect, but the ISIS controlled part of Syria is not much different in size than the part of Iran surrounding the Strait of Hormuz.
Conclusion
Actions in the next few weeks will determine whether the Carter Doctrine is dead letter or if the US can, through a vigorous and decisive campaign, restore its status as a guarantor of safe oil and gas transit out of the Gulf region. There is much uncertainty ahead but it is very likely that the few week timetables being discussed by Israeli and US officials are too short.
Iran gets a major vote in war termination and at this point, additional escalation and prolonged fighting are a plausible outcome (50% probability). We assess a 25% probability that the US announces a winding down of combat operations in the next three weeks that Iran does not reciprocate. Finally, we assess a 25% probability of a mutual ceasefire by mid-April.
With oil inventories drawing down, geography favoring Iran, and the munitions burden likely to be heavy, the structural forces shaping this conflict point toward a longer war.
Suggested Citation: Gabriel Collins, “Geography, Munitions, and Oil: Three Issues Pointing Toward a Long Iran War,” The Sinews of Civilization, Substack, 16 March 2026.