What Happens if the US Takes Control of Iran’s Most Valuable Asset?

President Donald Trump has reportedly ordered the deployment of an additional 2,500 Marines and sailors to the Persian Gulf, as tensions with Iran continue into their fourth week. The conflict has led to increased scrutiny of Iran’s strategic moves, specifically its control over oil tanker traffic in the crucial Strait of Hormuz. Attention is now also focused on Iran’s Kharg Island, a pivotal point in the region.

Kharg Island, situated about 16 miles from the Iranian mainland, is far more than just a geographical detail in the Gulf. It serves as the central hub for approximately 90 percent of Iran’s oil exports. The island’s location in waters that reach depths of up to 100 feet makes it ideal for accommodating large tankers, which cannot access the shallow shores of the mainland.

Securing control of Kharg Island would deliver a significant blow to Iran’s oil industry, potentially pushing Tehran to lift restrictions on the Strait of Hormuz. This waterway is vital, as it normally facilitates the flow of about 20 percent of the world’s oil supply.

However, seizing Kharg Island is no small feat. The newly deployed Marine Expeditionary Units are well-trained for rapid deployment in crisis situations, excelling in operations such as raids, evacuations, and limited territorial seizures. Yet, landing on Kharg does not automatically ensure a sustainable hold over the island.

Marine Expeditionary Units, now being deployed to the region, are trained to be deployed swiftly in a crisis. The units are ideal for raids, evacuations and limited seizures. But just because US forces are capable of landing on Kharg does not guarantee they would be able to hold it. 

American ground forces on Kharg would be vulnerable to attack from the Iranian mainland from missiles or drones. Amphibious American forces would also have to be escorted by air support to ensure they’re not attacked on the way to the target.

What opposition would a US landing face? It would not necessarily be a dramatic beach massacre straight out of an old war film. But some 8,000 people live on Kharg, and it’s likely that some military units are still functioning there. 

US troops could certainly expect sabotage of key facilities, mortar and small arms attacks, but these would be manageable. The greater danger is a dirty, layered counterattack. 

US control of Kharg would cripple Iran’s oil industry, prompting Tehran, the US hopes, to reopen the Straits of Hormuz, through which roughly a fifth of the world’s oil normally flows

The island lies in waters up to 100 feet deep, ideal for large tankers too massive to traverse the mainland’s shallow shoreline

US Marine Corps Chemical and Biological Immediate Response Force conducts a training exercise at Camp Lejeune in 2021

Iran entered the war with the Middle East’s largest ballistic missile stockpile — estimated 2,500 to 6,000 missiles-strong. Iran’s Fateh and Shahab short-range ballistic missiles have a range of 750km, and the newer Fattah-1 hypersonic missiles are designed to evade advanced air defense systems. 

That’s on top of a sizable drone arsenal and multiple underground facilities  — along with vast number of small boats and submarines capable of disrupting shipping across the Gulf.

There’s also the threat of a chemical weapons attack against US forces. Iran has deployed chemical weapons before — and might do so again if backed into a corner. Tehran’s battlefield chemical weapon capabilities, which they deployed during the 1980-1988 Iran-Iraq War, have been developed into a sophisticated arsenal.

Indeed, as of 2024, Israeli officials reported with ‘high confidence’ that Tehran has supplied weaponized pharmaceutical-based agents to proxies in Iraq and Syria.

Whilst all of these capabilities are now heavily degraded, the threat remains.

Ultimately, however, the nearby mainland coastline is the real threat. The region near Kharg is a mountainous hard-to-target network of potential bunkers and underground facilities, while coastal towns like Bushehr provide a multitude of short-range firing points. 

Would a blockade make more sense? In narrow military terms, probably yes. 

A blockade pressures Iran by exerting control over Kharg’s ports and the strait without leaving a Marine battalion exposed on a conspicuous target within Iranian range. 

Speaking with reporters last week, Trump called Kharg Island Iran’s ‘crown jewel,’ and said the US was ‘locked and loaded’ to destroy the oil hub – though, he added, ‘we chose not to do it’

US-led Combined Joint Task Force decontaminate themselves during a field training exercise at Kuwait’s Mubarak Airbase in 2003

Taking Kharg would require a Marine Expeditionary Unit — a self-sufficient force of about 2,200 Marines and sailors

Iran possesses thousands of drones and missiles, including these Shahab short-range ballistic missiles, which have a range of 500 miles

It is hardly clean or safe, but it is easier to envisage than a long-term occupation of an island under constant pressure from the mainland.

Regardless, there are no easy answers here – and almost certainly no swift journey home for US forces. 

Iran has warned that any attack on its oil and energy infrastructure would provoke retaliatory strikes against oil infrastructure and military partners in the region. The US can also expect increased pressure on shipping lanes, more retaliation by proxy groups and heightened global market anxiety. 

Capturing Kharg is not, in itself, an end to the war. It risks escalating the conflict with unpredictable consequences.

Yes, US Marines could likely secure the small island. But the real challenge is whether America could maintain control of it and easily resupply the force — all while mitigating Iranian retaliation from the mainland.

Andrew Fox is a Senior Fellow at the Henry Jackson Society and former British Army officer with service in the Parachute Regiment.