Why Did Iran And Iraq Go To War? Unpacking A Devastating Conflict

Jackie Quigley DVM 21 Jun 2025

The Iran-Iraq War, a brutal and protracted conflict that spanned nearly eight years, remains one of the 20th century's most devastating military engagements. Active hostilities began with the Iraqi invasion of Iran and lasted until the acceptance of United Nations Security Council Resolution 598 by both sides. The human cost was staggering, with estimates of total casualties ranging from one million to twice that number. Understanding why did Iran and Iraq go to war requires a deep dive into historical grievances, ideological clashes, and geopolitical ambitions that simmered for decades before erupting into full-scale combat.

This article aims to unravel the complex tapestry of factors that led to this catastrophic war, exploring the deep-seated tensions, the immediate triggers, and the prolonged suffering endured by both nations. We will examine the historical context, the key players, and the evolving dynamics of a conflict that reshaped the Middle East and left an indelible mark on its people.

The Deep Roots of Conflict: A Century of Tension
Geopolitical Landscape: Iran and Iraq on the Eve of War
The Ideological Divide: Revolution vs. Secularism
The Catalyst: Saddam's Invasion and Miscalculation
The Brutality Unfolds: War of Attrition and Cities
Iran's Resurgence and the Shifting Tides
International Intervention and the Road to Stalemate
The End of the War: Resolution 598 and Its Aftermath
Legacy and Lessons Learned
Conclusion

The Deep Roots of Conflict: A Century of Tension

The question of why did Iran and Iraq go to war cannot be answered without acknowledging the long history of animosity and unresolved disputes that predated the 1980 invasion. Tensions between Iran and Iraq began almost immediately after the establishment of the latter nation in 1921, in the aftermath of World War I. Carved out of the Ottoman Empire by British mandate, Iraq inherited a border with Persia (Iran) that had been a source of contention for centuries. One enduring source of conflict involved the Shatt al-Arab waterway, a crucial artery formed by the confluence of the Tigris and Euphrates rivers, which flows into the Persian Gulf. This waterway serves as a vital shipping lane for both nations, providing Iraq its only direct access to the sea. Historically, Iraq claimed sovereignty over the entire waterway, while Iran insisted on a thalweg principle, meaning the border should run along the deepest part of the channel. This dispute led to numerous skirmishes and diplomatic crises throughout the 20th century. The 1975 Algiers Accord, intended to resolve this and other border issues, saw Iran concede some territorial claims in exchange for shared sovereignty over the Shatt al-Arab. However, this agreement was deeply resented by Saddam Hussein, who viewed it as a humiliation imposed on Iraq. Beyond geographical disputes, ethnic and religious differences also fueled animosity. Iran is a predominantly Shia Muslim nation with a Persian ethnic majority, while Iraq, though also with a Shia majority, was ruled by a Sunni Arab minority under Saddam Hussein. Saddam often played on Arab nationalist sentiments, portraying Iran as a Persian threat to Arab identity. Iran, in turn, saw Saddam's regime as an oppressive, secular force suppressing Iraq's Shia majority. This complex web of historical grievances, border disputes, and ethno-religious fault lines laid the groundwork for future conflict. As Shaul Bakhash notes in his work on "the troubled relationship," these issues were deeply ingrained in the national psyches of both countries.

Geopolitical Landscape: Iran and Iraq on the Eve of War

By the late 1970s, the geopolitical landscape of the Middle East was undergoing significant shifts that would directly influence why did Iran and Iraq go to war. Iran is a Middle Eastern nation bordered by Turkey and Iraq to the west, Pakistan, Afghanistan, and Turkmenistan to the east, the Caspian Sea to the north, and the Persian Gulf to the south. Its strategic location, coupled with its vast oil reserves, made it a key player in regional and global affairs. In Iran, the Shah's pro-Western monarchy had been overthrown by the Islamic Revolution in 1979, ushering in an anti-Western, anti-monarchist, and fiercely independent Islamic Republic led by Ayatollah Ruhollah Khomeini. This revolution sent shockwaves across the region, particularly in neighboring Iraq. Saddam Hussein, then Iraq's strongman leader, viewed the new revolutionary Iran with a mixture of apprehension and opportunity. He feared the spread of Iran's Islamic revolutionary ideology to Iraq's own Shia majority, which could destabilize his regime. At the same time, he saw Iran's post-revolutionary chaos, characterized by purges within the military and government, as a moment of weakness to exploit. Iraq, under Saddam, had been building its military might, fueled by oil revenues and supported by both Western and Soviet bloc nations eager to counter Iran's revolutionary fervor. Saddam harbored ambitions of regional hegemony, envisioning Iraq as the dominant Arab power. He believed that a swift, decisive victory over a weakened Iran would not only resolve the Shatt al-Arab dispute in Iraq's favor but also elevate his status in the Arab world and secure Iraq's position as the Gulf's preeminent power. This convergence of fear, ambition, and perceived vulnerability set the stage for the impending conflict.

The Ideological Divide: Revolution vs. Secularism

A critical, often overlooked, dimension when asking why did Iran and Iraq go to war is the profound ideological chasm that separated the two nations in 1980. Iran, under Ayatollah Khomeini, was transformed into an Islamic Republic, committed to exporting its revolutionary ideals of Islamic governance and challenging what it perceived as corrupt, secular, and Western-backed regimes in the region. Khomeini frequently called for the overthrow of Arab monarchies and secular governments, including Saddam's Ba'athist regime in Iraq. Saddam Hussein, on the other hand, led a secular, nationalist Ba'ath Party that espoused pan-Arabism and socialist principles. His regime, while authoritarian, was fiercely anti-religious in its public policy and sought to suppress any form of religious dissent or political Islam within Iraq. The Shiite majority in Iraq, historically marginalized, became a particular concern for Saddam, who feared their allegiance to the revolutionary government in Tehran. This ideological clash was not merely theoretical; it manifested in overt actions. Iran actively supported Iraqi Shia dissidents and opposition groups, while Iraq provided sanctuary and aid to Iranian opposition figures, including the Mujahideen-e-Khalq (MEK). The rhetoric from both sides became increasingly vitriolic, demonizing the other's leadership and system of governance. Saddam viewed Khomeini's revolutionary fervor as a direct threat to his authority and the stability of his state, while Khomeini saw Saddam as an infidel tyrant who needed to be overthrown. This ideological confrontation provided a powerful, emotional justification for war, transforming a border dispute into a holy crusade for some and a necessary defense against religious extremism for others.

The Catalyst: Saddam's Invasion and Miscalculation

The immediate trigger for the Iran-Iraq War was Iraq's full-scale invasion of Iran on September 22, 1980. Active hostilities began with the Iraqi invasion of Iran, marking the official start of nearly eight years of conflict. Saddam Hussein, emboldened by what he perceived as Iran's post-revolutionary disarray and internal purges within its military, believed he could achieve a swift and decisive victory. He publicly abrogated the 1975 Algiers Accord, reclaiming full sovereignty over the Shatt al-Arab, and launched a multi-pronged offensive across the shared border. Saddam's motivations were multifaceted. As Hal Brands explores in his analysis, "Why did Saddam invade Iran?", key factors included: * **Reclaiming the Shatt al-Arab:** A primary objective was to reverse the perceived humiliation of the 1975 Algiers Accord and assert Iraqi control over the vital waterway. * **Regional Hegemony:** Saddam sought to establish Iraq as the dominant power in the Persian Gulf, filling the vacuum left by the Shah's downfall. * **Containing the Islamic Revolution:** He aimed to crush the nascent Islamic Republic and prevent the spread of its revolutionary ideology to Iraq's Shia population. * **Exploiting Perceived Weakness:** Saddam believed Iran's military, weakened by purges and the loss of Western support, would crumble quickly. He anticipated a short war, perhaps lasting only a few weeks. In the first stage, Iraq invaded Iran and made rapid progress, pushing deep into Iranian territory, particularly in the oil-rich province of Khuzestan. Iraqi forces seized towns and cities, including Khorramshahr, and aimed to cripple Iran's oil infrastructure. However, Saddam's initial assessment proved to be a grave miscalculation. Despite internal turmoil, the Iranian military, bolstered by fervent revolutionary guards (Pasdaran) and Basij volunteers, rallied with unexpected resilience. Their fierce resistance, often involving human wave attacks, halted the Iraqi advance in the Iranian desert. What Saddam had envisioned as a quick victory soon devolved into a brutal, grinding war of attrition, with devastating consequences for both nations. This failure to achieve a rapid triumph fundamentally altered the nature and duration of the conflict.

The Brutality Unfolds: War of Attrition and Cities

Once the initial Iraqi offensive stalled, the Iran-Iraq War transformed into a protracted and exceptionally brutal conflict, characterized by trench warfare, chemical attacks, and a devastating "war of the cities." The front lines became largely static, reminiscent of World War I, with both sides suffering immense casualties in costly, often futile, assaults. The use of chemical weapons by Iraq became a horrifying feature of the war. Saddam's regime deployed mustard gas and nerve agents against Iranian troops and Kurdish civilians, particularly in the later stages of the conflict, in blatant violation of international law. This added another layer of horror to the already gruesome battlefield. Perhaps one of the most chilling aspects was the "war of the cities." Both sides engaged in this indiscriminate targeting of civilian populations, launching ballistic missiles and airstrikes against major urban centers far from the front lines. Tehran, Baghdad, Isfahan, Qom, Basra, and other cities became targets, leading to widespread destruction and terror. This aerial bombardment and missile exchanges, designed to break the enemy's will, resulted in killing hundreds of thousands of civilians. Schools, hospitals, and residential areas were hit, causing immense suffering and mass displacement. The "war of the cities" exemplified the total nature of the conflict, where the distinction between combatant and civilian blurred, and the psychological impact on populations was profound. The sheer scale of destruction and loss of innocent lives underscored the extreme lengths to which both regimes were willing to go.

Iran's Resurgence and the Shifting Tides

After the initial shock of the Iraqi invasion, Iran gradually regained its footing and began to push back. The early stages of the war saw Iran on the defensive, struggling to organize its forces amidst the revolutionary purges. However, the deep religious fervor inspired by Ayatollah Khomeini, coupled with a strong sense of national pride in the face of invasion, mobilized a massive popular resistance. The regular army, the Islamic Revolutionary Guard Corps (IRGC), and the Basij volunteer militia coordinated their efforts, often employing innovative tactics and demonstrating immense sacrifice. Within two years of the invasion, Iran had recaptured its territories. Through a series of meticulously planned and ferociously executed offensives, Iranian forces managed to push Iraqi troops out of most of the occupied areas. A significant turning point came with the liberation of Khorramshahr in May 1982, a major strategic victory that boosted Iranian morale and demonstrated their military capability. Not only did Iran reclaim its land, but it also cut Iraq off from the sea ports, severely impacting Iraq's access to the Persian Gulf and its vital oil exports. This reversal of fortunes presented a new dilemma. Having achieved its primary objective of expelling the invaders, Iran faced a choice: negotiate a peace settlement or press on into Iraqi territory to achieve broader revolutionary goals, including the overthrow of Saddam Hussein's regime. Driven by Khomeini's unwavering conviction that Saddam was an infidel who must be removed, Iran chose the latter. This decision prolonged the war for another six years, transforming it from a defensive struggle into an offensive one, and further complicating the path to peace. Iran's newfound strength and determination to carry the war into Iraq escalated the conflict to an even more devastating level.

International Intervention and the Road to Stalemate

As the war dragged on and Iran began to gain the upper hand, international involvement became more pronounced, largely in an effort to contain Iran's revolutionary ambitions and prevent a complete Iraqi collapse. Many global powers, including the United States, feared the destabilizing effect of a victorious Iran and the potential spread of its radical ideology throughout the oil-rich Gulf region. This led to a tacit, and often overt, support for Iraq. Iraq received significant financial aid, military intelligence, and arms from various countries, including Saudi Arabia, Kuwait, and other Gulf states, as well as Western nations like the U.S., France, and the Soviet Union. This support helped Iraq sustain its war effort and rebuild its military, particularly after Iran's successful counter-offensives. The U.S., for instance, provided intelligence to Iraq and re-established diplomatic relations, effectively "tilting" towards Baghdad to counterbalance Tehran. The international community, particularly the United Nations, made numerous attempts to mediate a ceasefire and find a peaceful resolution. However, these efforts were largely unsuccessful for years due to the intransigence of both sides. Iran, now on the offensive, demanded the removal of Saddam Hussein, war reparations, and the prosecution of Iraqi leaders for war crimes. Iraq, while initially open to a ceasefire after its early setbacks, was unwilling to meet Iran's maximalist demands, especially regarding reparations. This external intervention, combined with the deeply entrenched positions of both belligerents, contributed significantly to the prolonged stalemate. Despite the immense human and economic costs, neither side was willing to concede, leading to years of grinding attrition warfare that seemed to have no end in sight. The world watched as this devastating conflict continued, fueling regional instability and drawing in more external actors.

The End of the War: Resolution 598 and Its Aftermath

The Iran-Iraq War, after nearly eight years of unimaginable bloodshed, finally began to wind down in 1988. By this point, both nations were utterly exhausted, their economies shattered, and their populations decimated. The human cost was staggering; estimated killed and wounded during the war range from one to two million. The sheer scale of casualties, combined with economic devastation, made continued fighting unsustainable.

Resolution 598 and Its Acceptance

The turning point came with United Nations Security Council Resolution 598, adopted in July 1987. This resolution called for an immediate ceasefire, the withdrawal of forces to international borders, the exchange of prisoners of war, and negotiations for a comprehensive peace settlement. Initially, Iran rejected the resolution, still clinging to its demands for Saddam's overthrow and reparations. However, a series of renewed and intense Iraqi offensives, coupled with increasing international pressure and a lack of support from its allies, finally forced Iran's hand. When Iraq began launching several successive attacks into Iran and potentially putting an end to the stalemate, Iran, facing a dire military situation and immense domestic pressure, agreed to the resolution and put an end to the war. Ayatollah Khomeini famously described his decision to accept the ceasefire as "drinking the chalice of poison," underscoring the profound reluctance and bitterness with which Iran ended the conflict.

Post-Ceasefire Negotiations

Fighting was ended by a 1988 ceasefire, but the path to a lasting peace was arduous. While the guns fell silent, the underlying issues remained. Iraq agreed to these conditions, but Iran would not normalize relations unless Iraq paid war reparations and accepted responsibility for initiating the conflict. These demands proved to be a significant sticking point, delaying full normalization for years. The ceasefire was merely a cessation of hostilities, not a peace treaty.

The Long Road to Normalization

The resumption of normal diplomatic relations and the withdrawal of troops did not take place until 1990. It took two more years of painstaking negotiations, often mediated by the UN, to achieve a semblance of peace. Even then, the legacy of the war, including unresolved border issues, the fate of prisoners of war, and the question of reparations, continued to cast a long shadow over bilateral relations. The 1990 Iraqi invasion of Kuwait, ironically, played a role in accelerating the finalization of peace with Iran, as Saddam sought to secure his eastern flank.

The Staggering Human Cost

The Iran-Iraq War stands as a stark reminder of the devastating consequences of prolonged conflict. Estimates of total casualties range from one million to twice that number, making it one of the deadliest conventional wars of the late 20th century. Beyond the immediate deaths, millions more were wounded, displaced, or suffered long-term psychological trauma. The economic toll was equally catastrophic, with both nations' infrastructures severely damaged and their development set back by decades. This is a bold claim in an age that has been packed with conflict since 1988, so it deserves to be highlighted as one of the most destructive.

Legacy and Lessons Learned

The Iran-Iraq War left an indelible mark on both nations and the broader Middle East. For Iran, the war solidified the Islamic Republic's grip on power, fostering a deep sense of national resilience and self-reliance in the face of external threats. It also profoundly shaped its foreign policy, leading to a continued emphasis on defensive capabilities and the development of asymmetric warfare strategies. The war created a generation of veterans and martyrs, whose sacrifices continue to be commemorated and whose experiences inform Iran's national narrative. For Iraq, the war was a pyrrhic victory. While Saddam Hussein managed to survive and avoid overthrow, the conflict left his country deeply indebted, its economy in ruins, and its military severely depleted despite the massive international aid received. The war's financial burden directly contributed to Saddam's subsequent decision to invade Kuwait in 1990, setting in motion a chain of events that would ultimately lead to his downfall. The use of chemical weapons by Iraq during the war also remains a dark stain on its history, with long-term health consequences for survivors. The conflict underscored the dangers of unresolved historical grievances, unchecked regional ambitions, and ideological extremism. It demonstrated how easily a localized dispute can escalate into a prolonged, devastating war when combined with political miscalculation and external interference. The sheer scale of human suffering, the widespread use of brutal tactics, and the long-lasting geopolitical ramifications serve as a grim lesson for future generations about the true cost of armed conflict. The war's legacy continues to influence regional dynamics, contributing to the complex and often volatile relationships between Middle Eastern states.

Conclusion

The question of why did Iran and Iraq go to war is not answered by a single cause but by a confluence of deeply intertwined factors: centuries of unresolved border disputes, particularly over the Shatt al-Arab; the ideological clash between Iran's revolutionary Shiism and Iraq's secular Ba'athism; and Saddam Hussein's strategic miscalculation of Iran's post-revolutionary vulnerability. What began as a swift invasion quickly devolved into a brutal, eight-year war of attrition, marked by chemical attacks, the "war of the cities," and an estimated one to two million casualties. The conflict was a devastating human tragedy and an economic catastrophe for both nations, leaving deep scars that persist to this day. While the fighting ended with the 1988 ceasefire and the acceptance of UN Resolution 598, the path to full diplomatic normalization was protracted, not fully achieved until 1990. The Iran-Iraq War stands as a stark reminder of the immense human cost of unchecked ambition and unresolved grievances, a conflict that reshaped the Middle East and continues to cast a long shadow over its geopolitical landscape. We hope this comprehensive overview has shed light on the complex reasons behind this pivotal conflict. What are your thoughts on the long-term impacts of the Iran-Iraq War? Share your perspectives in the comments below, and don't forget to explore our other articles on historical conflicts and their lasting legacies.

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