March 30, 2026

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U.S. Combat Force Buildup Sets the Stage for Potential Ground Offensive in Iran

U.S. Central Command via AP

As the U.S.-Israeli military campaign against Iran enters its fifth week with no diplomatic resolution in sight, global officials and experts are increasingly turning their attention to the possibility that U.S. Donald President Trump will escalate the conflict by inserting ground combat forces into Iranian or Iran-controlled territory. Assessments of potential U.S. escalation flow from announcements and reports over the past two weeks that the Department of War is flowing ground forces to the theater, although without stipulating what, if any, specific missions they might perform.

U.S. officials assert they cannot wind down the conflict unless and until Iran relinquishes its essential control over the flow of energy and other commercial shipments through the strategic Strait of Hormuz chokepoint, among other conditions. Yet Iran’s surviving leaders, ruling in a decidedly hardline power structure dominated by Islamic Revolutionary Guard Corps (IRGC) commanders, believe they have gained a stranglehold on the global economy and have the strategic upper hand over Trump.

Observing no softening of Iran’s negotiating position, the Department of War and press reports demonstrate an expanding buildup of U.S. ground combat forces in the theater. U.S. officials say the buildup is intended to provide Trump with a broader array of options to achieve U.S. objectives, including reopening the Strait to free and unfettered traffic. Yet the planning appears to reflect frustration within the Trump team that not only has the regime survived the campaign, but also that Tehran believes its disruption of the global energy market and economy gives it the right to dictate terms at the bargaining table.

Seeking to upend Tehran’s calculations, U.S. officials have announced the deployment of two Marine Expeditionary Units (MEU) to the region, with a total of nearly 5,000 combat-ready Marines, accompanied by supporting forces, combat aircraft including F-35 Stealth fighters, Osprey vertical take-off planes, attack helicopters, and artillery. U.S. Central Command (CENTCOM) announced Saturday that the 31^st MEU, aboard the USS Tripoli amphibious assault ship, was the first of the two MEUs to arrive in theater. The other MEU, the 11^th, based on the USS Boxer, is about a week away. Last week, the Department of War announced that 2,000–3,000 paratroopers from the 82nd Airborne Division were also being ordered to the region, equipped with armored vehicles and logistical support. The Wall Street Journal reported Friday, quoting officials with knowledge of the planning, that the Pentagon is considering sending another 10,000 ground troops to the Middle East — a deployment that would bring the U.S. ground force buildup to nearly 20,000. The additional forces supplement the 50,000 U.S. forces in the region, though most of those units are engaged in the air-strike effort.

Reacting to widespread U.S. official and public concerns that any movement of ground forces into Iran could slip into a quagmire, U.S. officials deny that a decision to introduce ground troops into Iran has been made. They argue the deployments, even if not sent into combat, are a form of coercive diplomacy and provide leverage in settlement talks with Iran. The presence in the region of a significant U.S. ground combat force presumably threatens regime leaders with a loss of territory and economic assets unless they accept the 15 stringent U.S. demands submitted to Iran last week via regional intermediaries. The buildup also expands the options available to U.S. leaders if settlement talks with Iran fail. Secretary of State Marco Rubio told ?reporters, after meeting G7 counterparts in France, that the U.S. could achieve its aims without ground troops, but that the forces are flowing to the region “to give the President maximum optionality and maximum opportunity to adjust the contingencies, should they emerge.”

However, Iranian leaders assert they are undaunted by the threat of a U.S. ground incursion. Iranian forces reportedly have been laying mines and enhancing their defensive preparations at sites where they believe the U.S. might try to land troops. On Sunday, Iran’s Majles speaker (parliament) Mohammad Bagher Ghalibaf — believed by U.S. officials to have become the regime’s de facto civilian leader — said Iranian forces “are waiting for the arrival of American troops on the ground to set them on fire and punish their regional partners forever.” The Iranian threats might also represent an effort to deter U.S. ground action that Tehran might assess as incapable of being repelled.

A key question is how U.S. ground troops, if ordered into battle, would help achieve the core objectives of Operation Epic Fury. The Washington Post reported Saturday that the Pentagon is preparing plans for weeks of ground operations that would fall short of a full-scale invasion, consisting instead of raids by a mix of Special Operations Forces (SOF) and infantry. An all-out invasion of Iran, intended to remove the regime from power in a country of more than 90 million, would no doubt require many times the number of ground troops ordered to deploy to the region.

Any ground incursion into Iran-held territory, even if limited, risks the loss of U.S. personnel to a multiplicity of threats from Iran’s drone and missile arsenal, direct and indirect ground fire, roadside and other improvised explosive devices (IEDs), and suicide bombings. Iran is known to possess a significant storehouse of first-person-view (FPV) drones, such as those Ukraine has used to cause large-scale casualties to Russia’s invasion force. And experts warn that the introduction of ground troops risks “mission creep” — an expansion of the ground operation, likely in response to Iran’s reactions, to achieve objectives broader than initially envisioned. Some officials worry that a small ground offensive has the potential to evolve into a broader operation to capture towns and cities in order to destabilize Iran’s regime.

The publicly discussed possible U.S. ground missions aim to achieve a variety of objectives. One widely discussed operation that might be performed by a small U.S. force includes trying to secure Iran’s 460 kilograms of 60 percent enriched uranium believed to be under rubble at Iran’s Isfahan uranium conversion facility. Experts fear Iran might be able to recover that material and work toward developing up to 11 nuclear weapons. However, the uncertain location and state of the material likely would require a risky, extended presence well inside Iranian territory.

Another mission might include the seizure of Iran’s Kharg Island, which contains the terminals from which 90 percent of Iran’s oil is exported, with the intent of compelling Iran to open the Strait of Hormuz and accept other U.S. demands. General Joseph Votel, former commander of CENTCOM, estimates that 1,500 Marines are enough to secure the island, which is about 15 miles off Iran’s coast. Trump publicly threatened to destroy the oil installations on Kharg unless Tehran ends its blockage of traffic through the Strait of Hormuz, 300 miles down the coast from Kharg. However, forces holding that or any other Iranian island would be vulnerable to counterattacks and, despite the potentially catastrophic impact on Iran’s economy, might not force regime leaders to reopen the Strait. A cutoff of Iran’s oil exports would also deplete global oil supplies and cause oil prices to escalate even further.

Experts assess that if the primary U.S. objective is to fully reopen the Strait, other islands in the Strait are more pivotal than Kharg. Seven of these islands — Abu Musa, Greater Tunb, Lesser Tunb, Hengam, Qeshm, Larak, and Hormuz — form what researchers at Sun Yat-sen University in China call Iran’s “arch defense.” A 2022 paper by two Sun Yat-sen researchers, Enayatollah Yazdani and Ma Yanzhe, concluded that Abu Musa and the Tunbs, the smallest of the seven and at the western end of the arch, are key to controlling the Strait. Experts assess that the U.S. forces arriving in the region would likely be sufficient to gain control of these islands, although U.S. troops occupying them would be vulnerable to Iranian fire. And, capturing the islands would not necessarily impinge on Iranian sovereign territory per se, because Iran forcibly seized the three islands from the UAE in 1971, during the reign of the Shah. The status of the islands has been the subject of a UAE-Iran dispute ever since. A U.S. capture of the islands, even if only held by U.S. forces temporarily, might resolve the territorial dispute in favor of the UAE, a U.S. ally, although Iran is likely to want to recapture them.

Some argue a target nearly certain to disrupt Iran’s closure of the Strait, and perhaps destabilize the regime more generally, is the city of Bandar Abbas. The port city is the main hub for Iran’s naval command structure, with a population of about 700,000. However, an operation to capture Bandar Abbas would likely require additional U.S. forces, as well as pose significantly more risks, insofar as the city is on the Iranian mainland itself.