Despite the intensity of U.S. and Israeli airstrikes on Iran, Washington continues to approach the question of a ground war with caution, sending mixed signals. President Donald Trump has not entirely ruled it out, stating: “I am not saying there will not be forces on the ground, we may not need them, or if necessary.”
Between an open ended air campaign and unresolved signals about a possible shift to ground operations, an old question resurfaces: can Iran be penetrated by land as it was at earlier moments in its modern history, or has the cost today become far greater?
A review of Iran’s modern history reveals two prominent cases of border breaches: the rapid Anglo Soviet invasion in 1941, and the large scale Iraqi attack at the outbreak of the 1980 war. But what has changed today in geography, military capability, state structure, and deterrence tools to make any ground invasion a highly costly gamble?
The Anglo Soviet Invasion of Iran in 1941
On the eve of the Second World War, Reza Shah Pahlavi, founder and ruler of the Pahlavi state, sought to keep Iran neutral between the warring powers. However, Britain and the Soviet Union feared growing German influence in Tehran and its impact on oil supplies and transport routes to the Soviet Union.
At dawn on August 25, 1941, the Anglo Soviet alliance launched Operation Countenance. British army units and the Indian 8th Division crossed the Shatt al Arab from Basra toward Abadan in southwestern Iran, quickly seizing its oil refineries with support from a small naval force.
At the same time, other British units advanced from Khanaqin on the Iraqi border, pushing into the Naft Shah oil field before crossing the Pai Tak pass toward Kermanshah after Iranian defenders withdrew.
From the north, three Soviet armies attacked Iran عبر the Caucasus, while amphibious landings took place in Bandar Pahlavi on the Caspian Sea coast. Forces then advanced toward Maku, Sanandaj, and Qazvin.
Iranian forces were poorly trained and lacked tanks and air power. Reza Shah refused to destroy roads and railway lines to slow the advance, which facilitated the rapid invasion.
By August 30, British and Soviet forces met in Sanandaj and Qazvin. Iranian defenses collapsed, and the Shah agreed to surrender. He was forced to abdicate in favor of his son Mohammad Reza on September 16.
The occupation marked a decisive تحول. After the signing of a tripartite treaty in January 1942, the Allies were permitted to keep their forces until the end of the war, and Iran was turned into the “Persian Corridor” to supply the Soviet Union with weapons and aid.
The success of the invasion was not only due to numerical superiority, with Anglo Soviet forces mobilising around 200,000 troops against nine weak Iranian divisions, but also due to weak Iranian leadership, failure to mobilise the population, and inability to utilise mountainous terrain. The Allies also relied on amphibious forces and modern air power that secured control of the skies.
These factors made the invasion rapid and low cost for the Allies, leaving a bitter memory in Iranian consciousness of the collapse of the monarchy in the face of easy foreign penetration.
The Iraqi Invasion of Iran in 1980
Eighteen months after the Islamic Revolution, Iraqi President Saddam Hussein saw an opportunity to seize territory in the oil rich Khuzestan region and weaken the new system. On the morning of September 22, 1980, Iraqi forces launched airstrikes on ten Iranian airbases, followed by a ground invasion across three axes.
On the northern front, Iraqi forces quickly captured Qasr Shirin to cut the strategic road between Baghdad and Tehran.
In the center, the army seized Mehran in Ilam province.
In the south, three armoured divisions and two mechanised divisions crossed the Shatt al Arab toward Khorramshahr, Abadan, and Ahvaz.
In the first days, Iraqi forces advanced about 80 kilometres into Khuzestan and nearly isolated Khorramshahr and Abadan from Ahvaz. However, Iraqi calculations proved incorrect. Airstrikes failed to destroy Iran’s air force, as runways were targeted instead of aircraft, allowing Iran to retain its F 4 bombers and launch counterstrikes.
On the ground, Iraqi forces faced fierce resistance in southern cities. Abadan held out despite siege, while Khorramshahr fell after two months of urban combat that cost Iraq around 6,000 dead.
Initial gains in the north and center were achieved, but Iraqi forces halted at Dezful and Ahvaz and failed to advance deeper.
The failure of the invasion resulted from several factors:
Iran released detained pilots and deployed its regular army alongside the Revolutionary Guard and Basij volunteers, creating a broad human defense.
Many Arabs of Khuzestan joined the resistance rather than aligning with Baghdad, denying Iraq a local “Trojan horse.”
The Iraqi army made tactical errors, focusing on dispersed objectives and failing to prioritise advancing toward Ahvaz or destroying the Dezful airbase. Its command structure was also not prepared for urban warfare.
Thus, the rapid incursion turned into a prolonged war of attrition. Iran regained occupied territories in 1981 to 1982. Despite achieving surprise, Iraq failed to topple the Iranian state or force its surrender. Instead, it strengthened the revolutionary discourse of “sacred defense” and led to wide popular mobilisation.
Why Does Ground Penetration Appear More Complex Today?
The current war is largely confined to air and sea, as Washington declares it will not repeat the scenarios of Iraq or Afghanistan that drained it for years.
U.S. Secretary of War Pete Hegseth stated that the campaign’s objectives are to destroy missile and nuclear capabilities, not to “build a state,” adding: “You do not need to send 200,000 troops there and stay for 20 years.” Trump himself linked the ground option to absolute necessity, suggesting it may not be required.
This caution reflects several factors that make a ground invasion more costly than ever:
1. Geography
Iran today is a vast country exceeding 1.6 million square kilometres, with complex and rugged terrain. The Zagros mountain range along the Iraqi border, the Alborz mountains in the north, and vast internal deserts provide significant defensive advantages.
2. Population Density
With a population of around 85 million, spread across large cities and rural مناطق, any invading force would need to occupy densely populated urban centres and confront ideologically driven popular resistance shaped by the Iran Iraq war and subsequent asymmetric conflicts.
3. Military and Security Experience
Over four decades, Iran has accumulated extensive military experience. The Revolutionary Guard and Basij forces have evolved from a popular militia into an ideological institution with land, air, and naval units, along with a broad volunteer network, as demonstrated during the June 2025 confrontation and the current war.
According to a report by the Center for Strategic and International Studies, Iran possesses “the largest and most diverse missile systems in the Middle East,” with thousands of ballistic and cruise missiles, some capable of reaching “Israel” and Eastern Europe, with improved accuracy over the past decade.
Iran also has long range drones and missile capabilities among its allies in Iraq, Lebanon, and Yemen, meaning any ground force would face continuous threats to supply lines and rear bases.
4. Combat Experience
Iran has become highly experienced in asymmetric warfare. Its defensive doctrine based on “centralised planning and decentralised execution” has enabled it to absorb initial shocks in the current war and continue launching missiles despite intense electronic warfare strikes.
Its experience in supporting militia movements across the Middle East and deploying advisory units also allows it to open multiple fronts against its adversaries.
Accordingly, repeating the scenarios of 1941 or 1980 in a contemporary form appears to be a high risk political and military gamble, especially amid divisions in U.S. public opinion. Recent polls show that support for the strikes stands at only 27 percent.
