Preparing for Ground War

Welcome back to the MBN Iran Briefing.

Tehran is sending signals and preparing for a possible ground invasion. Find out more below.

Quote of the Week

“[We are] waiting for the arrival of American troops on the ground to set them on fire and punish their regional partners forever.”

– Mohammad-Bagher Ghalibaf, Iran’s parliament speaker

On Friday, 3,500 U.S. Marines arrived in the Middle East aboard the USS Tripoli. The 82nd Airborne is on its way. The Pentagon is drawing up plans for ground raids on Iranian territory. And in Iran, the government has opened up to children as young as twelve to register at mosques and registration booths on central squares to serve as combatants. Women called “the lionesses” are being recruited to defend Iran on the ground.

The question now dominating Washington’s war councils, Gulf capitals, and Tehran’s defense planning is a different and more dangerous one: What happens if U.S. boots hit Iranian soil?

The Pentagon confirmed it is preparing plans for ground operations, including raids on Kharg Island and coastal sites near the Strait of Hormuz, even as the White House insisted no decision has been made. U.S. President Donald Trump told the Financial Times on Sunday that he is still weighing whether to seize Kharg, the island that handles ninety percent of Iran’s oil exports, before adding “Maybe we take it, maybe we don’t.”

Tehran has spent the past month building a layered defense. The goal may be not to win a ground war against the United Statesp, but to make one so costly that the political will to continue it collapses in the West.

Iran is mobilizing every layer of its society for this fight.

Iran’s ground defense posture can be understood through four distinct but overlapping layers, each serving a different strategic purpose.

Deterrence

The first and in some ways most important layer of defense is to make sure a shot is never fired. Iran has worked hard to drive home the message that any ground operation would be catastrophically costly. Target audiences include the Trump administration, the U.S. public, Gulf states privately urging Washington to hold back, and its own domestic public.

Iran’s parliament speaker Mohammad-Bagher Ghalibaf has warned that Iranian forces are “waiting” for U.S. troops. Iranian state media claims that over a million combatants are prepared for a ground war – in their words, “a wave of enthusiasm has emerged among Iranian ground fighters to create a ‘historical hell’ for the Americans on Iranian soil.” In a headline typical of the regime’s public stance – “Iran’s Naval Basij Turned Hormuz into a Graveyard for U.S.-Israeli Arrogance” – one regime source asserted that a “naval Basij of 55,000 volunteers and 33,000 vessels” awaits a possible invasion.

These claims are, of course, performative rather and don’t reflect actual military capabilities.

Gulf states have privately warned Washington that occupying Kharg Island would trigger Iranian retaliation against Gulf infrastructure and prolong the conflict indefinitely.

Denial

If deterrence fails, Iran’s second layer is designed to make the physical act of landing as lethal as possible.

On Kharg Island itself, Iran has deployed additional ground forces, shoulder-launched anti-aircraft missiles, and extensive anti-personnel and anti-armor minefields along shorelines and likely amphibious landing zones. Images circulating on social media, purportedly from Iranian personnel on the island, show drone units in fortified positions, which analysts have assessed as first-person-view kamikaze systems intended for close-range attacks on landing craft. These would supplement underground trenches and bunkers that have been constructed to survive initial air strikes and allow defenders to keep fighting through the ground phase.

U.S. Central Command’s near-constant overhead surveillance has observed these preparations directly, including physical changes to the terrain consistent with trap-laying.

Before any amphibious force even reaches Kharg, it must navigate the arch of seven islands – Abu Musa, Greater and Lesser Tunb, Hengam, Qeshm, Larak and Hormuz – that form Iran’s layered maritime defense across the Hormuz strait. Each would need to be cleared of Iranian military positions before U.S. warships could safely proceed into the northern Gulf. The March 13 U.S. strikes on Kharg degraded existing HAWK surface-to-air missiles and Oerlikon anti-aircraft guns, but Iran has since reinforced the island, and the proximity to the mainland means rocket and artillery cover would persist during any landing attempt.

Attrition

The third layer assumes the landing happens and Iran attempts to inflict damage on the occupying force. This is the mosaic defense doctrine in its purest form, built on Iran’s reading of the U.S. experience in Iraq after 2003.

Units are decentralized and semi-autonomous, operating on pre-assigned general instructions rather than real-time command direction. The loss of a headquarters, a general, or even a regional command does not cascade into collapse. Iranian foreign minister Abbas Araghchi said early in the war that some units were already “independent and somewhat isolated” and acting on standing orders. Underground bunker networks have likely survived the bombing campaign. Hundreds of IRGC speedboats provide persistent harassment capability against larger vessels. The aforementioned “naval Basij,” drawing on fishing communities, dock workers and local coastal knowledge across southern Iran’s ports and islands, provides a distributed maritime attrition force that is difficult to neutralize from the air because it is woven into the civilian fabric of the coastline itself.

Internal control

The fourth layer is the one least discussed in military terms but arguably the most consequential. When the IRGC sets up checkpoints staffed partly by twelve-year-old volunteers and runs registration drives through mosques, it is not only preparing to fight Americans on Kharg. It is also making sure that the people of Tehran, Mashhad, and Isfahan do not take advantage of the chaos of war to rise up again.

Article 151 of the Iranian constitution requires the government to provide military training to all citizens so that “all citizens will always be able to engage in the armed defense of the Islamic Republic.” The regime used child soldiers for “martyrdom operations” in the 1980-88 Iran-Iraq war. Judging from its willingness to mow down thousands of its own citizens in January, there is no reason to believe the regime will pull any punches if it is fighting for its very existence, whether against foreign forces or its own people.

ESSENTIAL READING:

The Houthis

Yemen’s Houthi movement entered the Iran war on Saturday, launching its first strikes on Israel since hostilities began Feb. 28.

“We are preparing for a multifront war,” an Israeli military spokesperson said following the Houthi attack.

The Houthis’ entry matters not because two intercepted missiles threatened Israel, but because of what comes next. With the Strait of Hormuz already effectively closed, the Houthis sit astride the only remaining exit from the Arabian Peninsula: the Bab al-Mandab, which translates as “the Gate of Tears.” If they move to choke that corridor too, the world’s energy markets face a crisis with no historical precedent.

Some key reading about the Houthis and their entry into the war:

1. “Yemen’s Houthis Have Entered the Iran War. What You Need To Know” – Time, March 28. The single best explainer on the entry and why it took a month. The key analytical thread: The Houthis likely “tried their best to stay out of this war” but ultimately could not ignore years of Iranian backing. The critical next question is whether their involvement remains limited to occasional strikes on Israel that cause little damage, or whether they resume Red Sea shipping attacks. The second scenario would significantly amplify pressure on the U.S.
2. “What do Houthi attacks on Israel mean for the Iran war?” – Chatham House, March 29. The Houthi entry threatens to derail fragile peace efforts in Yemen and could resume the Saudi-Houthi war that ended in a fragile truce in 2022. The decision also risks reinforcing perceptions of the group as an extension of Iranian influence rather than a Yemeni political force.
3. “Houthi attacks open new front, threaten Red Sea shipping” – France 24, March 29. The clearest account of the double-chokepoint stakes and the Saudi dimension. With Hormuz effectively shut, Saudi Arabia has seen tankers diverted to its Red Sea port of Yanbu, but this is the kingdom’s last secure oil outlet. If Bab al-Mandab is also threatened, Riyadh may abandon its careful neutrality in the war, potentially even retaliating against Iran.
4. “The Houthis Must Decide: Join Iran’s War or Abandon Iran” – Stimson Center.

Published just after the outbreak of the war. The most rigorous strategic framing of the factors going into the Houthis’ decision to enter the war or stay out. Iran faces its own calculation: It must balance the benefits of Houthi involvement against the risk of accelerating the group’s decapitation, as befell the IRGC’s own senior leadership and Hezbollah before them..