Unraveling The Iran-Iraq War Causes: A Deep Dive

Mervin Schuppe PhD 29 Jun 2025

The Iran-Iraq War, a devastating conflict that raged for nearly eight years in the 1980s, remains one of the 20th century's most brutal and complex geopolitical events. Understanding the myriad of factors that led to this immense human tragedy is crucial for comprehending the modern Middle East. From political tensions to territorial disputes, the conflict did not erupt in a vacuum; it was the culmination of centuries of rivalry, compounded by immediate political ambitions and ideological clashes. This article delves deep into the multifaceted Iran-Iraq War causes, examining the historical animosities, immediate triggers, and underlying motivations that propelled two neighboring nations into a prolonged and bloody confrontation.

The question of "Why did Iraq and Iran go to war?" is complex, involving a tapestry of historical grievances, ideological differences, and strategic calculations. While active hostilities began with the Iraqi invasion of Iran, the roots of the conflict run far deeper than a single act of aggression. It is a story of ancient rivalries, modern ambitions, and the tragic consequences of unresolved disputes.

The Deep Roots of Conflict: A Historical Perspective
- Ancient Rivalries: Persia vs. Mesopotamia
The Spark: Iraq's Invasion and Stated Justifications
- Border Skirmishes and Defensive Claims
Saddam Hussein's Motives: Two Main Drivers
The Iranian Revolution's Impact: A Catalyst for War
- Ayatollah Khomeini's Critique of Secular Iraq
Territorial Disputes and the Shatt al-Arab
International Dynamics and Regional Power Plays
The Devastating Legacy: Consequences and Chemical Weapons
- The Human and Environmental Toll
Lessons Learned: Preventing Future Conflicts

The Deep Roots of Conflict: A Historical Perspective

To truly understand the Iran-Iraq War causes, one must look beyond the immediate events of 1980 and delve into the long, often contentious history shared by these two nations. The war followed a long history of border disputes, but the animosity was far more profound than mere lines on a map. It was a clash of civilizations, cultures, and political systems that had been simmering for centuries.

Ancient Rivalries: Persia vs. Mesopotamia

The states of Persia (Iran) and Mesopotamia (Iraq) had been rivals since they were ancient civilizations. This historical antagonism is a fundamental, albeit often overlooked, aspect of the Iran-Iraq War causes. For millennia, the lands corresponding to modern-day Iran and Iraq have been centers of powerful empires – from the Achaemenid Persians and the Sasanian Empire to the various Mesopotamian kingdoms and later the Ottoman Empire. These empires frequently clashed over territory, trade routes, and regional dominance. This deep-seated historical rivalry fostered a mutual suspicion and sense of competition that persisted into the 20th century.

Modern Iran, officially an Islamic Republic, is a cradle of civilization, inhabited by a diverse population and maintaining a rich and distinctive cultural and social continuity dating back millennia. Iran, a mountainous, arid, and ethnically diverse country of southwestern Asia, ranks 17th globally in both geographic size and population. Tehran is the nation's capital, largest city, and financial center. This proud and ancient heritage often contrasted with Iraq's more recently formed national identity, which emerged from the dissolution of the Ottoman Empire, leading to a complex dynamic of perceived superiority and historical grievance on both sides.

The Spark: Iraq's Invasion and Stated Justifications

While the underlying tensions were historical, the active hostilities began with the Iraqi invasion of Iran in September 1980. This invasion marked the official start of a conflict that lasted for nearly eight years. Iraq's stated reason for initiating the war was defensive. The government in Baghdad claimed that Iranian forces were staging raids across their common border and that these incursions necessitated a robust response to protect Iraqi sovereignty and territory. This narrative was crucial for Saddam Hussein's regime to justify its actions both domestically and internationally.

Border Skirmishes and Defensive Claims

Leading up to the invasion, there indeed had been a series of escalating border skirmishes. These incidents, often minor in scale, were amplified by both sides to fuel nationalistic fervor and justify military build-ups. Iraq accused Iran of violating the 1975 Algiers Agreement, which had settled some border disputes, particularly concerning the Shatt al-Arab waterway. Baghdad argued that Iran's post-revolution government was no longer adhering to the terms of this agreement and was actively seeking to destabilize Iraq through cross-border provocations and ideological incitement.

However, many analysts view Iraq's "defensive" claims as a pretext for a more aggressive agenda. The scale of the Iraqi invasion, involving a multi-pronged assault deep into Iranian territory, suggested ambitions far beyond mere border protection. It was clear that Saddam Hussein sought to achieve significant strategic objectives, believing Iran to be vulnerable in the wake of its revolution.

Saddam Hussein's Motives: Two Main Drivers

There are two main motives ascribed to Saddam Hussein’s decision to invade Iran, which form critical Iran-Iraq War causes. These motivations were intertwined, reflecting both Saddam's personal ambitions and Iraq's strategic calculations in a rapidly changing regional landscape:

Regional Hegemony: Saddam Hussein harbored ambitions of establishing Iraq as the dominant power in the Persian Gulf region. With Iran seemingly weakened and isolated after its 1979 Islamic Revolution, Saddam saw a golden opportunity to assert Iraqi supremacy. He believed that a swift victory over Iran would elevate Iraq to a leadership position among Arab states, particularly given the perceived decline of Egypt's influence after its peace treaty with Israel. This ambition was not just about military might but also about political prestige and economic leverage, especially concerning oil production and pricing.
Exploiting Iranian Weakness and Containing the Revolution: The Islamic Revolution in Iran had dramatically altered the geopolitical landscape. The new revolutionary government, led by Ayatollah Ruhollah Khomeini, was fiercely anti-Western and actively sought to export its revolutionary ideology to neighboring countries, particularly those with significant Shi'ite populations, like Iraq. Ayatollah Khomeini was critical of Iraq's secular Ba'athist regime, which was predominantly Sunni but ruled over a Shi'ite majority. This ideological challenge posed a direct threat to Saddam's authoritarian rule and the stability of his regime. Saddam likely calculated that Iran's military, weakened by purges of Shah-era officers and international sanctions, would be no match for Iraq's well-equipped and battle-hardened forces. He aimed to deliver a decisive blow, perhaps even topple the revolutionary government, and thereby neutralize the ideological threat emanating from Tehran.

These two primary motives converged, leading Saddam to believe that a preemptive strike against Iran would be a low-risk, high-reward gamble that would secure Iraq's regional standing and protect his regime from revolutionary contagion.

The Iranian Revolution's Impact: A Catalyst for War

The 1979 Islamic Revolution in Iran was a seismic event that profoundly impacted regional stability and served as a major Iran-Iraq War cause. The overthrow of the pro-Western Shah and the establishment of an Islamic Republic under Ayatollah Khomeini sent shockwaves throughout the Middle East, particularly in neighboring Iraq. The revolution was not just a domestic affair; it carried a powerful ideological message of Islamic revivalism and anti-imperialism that resonated with Shi'ite communities across the region, including Iraq's Shi'ite majority.

Ayatollah Khomeini's Critique of Secular Iraq

Ayatollah Khomeini was openly critical of Iraq's secular Ba'athist government, viewing it as an illegitimate and un-Islamic regime. He called for the overthrow of Saddam Hussein and encouraged Iraqi Shi'ites to rise up against their government. This direct ideological challenge deeply unnerved Saddam Hussein, who feared that Khomeini's revolutionary fervor could ignite widespread unrest among Iraq's Shi'ite population, potentially leading to a domestic uprising that would threaten his rule. The rhetoric from Tehran was seen in Baghdad as a direct interference in Iraq's internal affairs and a grave threat to its national security. This ideological antagonism was a powerful accelerant for the conflict, transforming a traditional border dispute into a holy war for some, and a struggle for survival for others.

Territorial Disputes and the Shatt al-Arab

While often overshadowed by ideological and political factors, long-standing territorial disputes were a significant Iran-Iraq War cause. The most contentious of these was the dispute over the Shatt al-Arab waterway, known in Iran as Arvand Rud. This river, formed by the confluence of the Tigris and Euphrates, flows into the Persian Gulf and serves as the border between the two countries for part of its length. Its strategic importance lies in its role as a vital shipping lane for both nations' oil exports and a gateway to their respective ports.

The border along the Shatt al-Arab had been a source of contention for centuries, with various treaties attempting to define the boundary. The 1975 Algiers Agreement, signed by Iraq and Iran, was meant to resolve this issue by recognizing the thalweg (the deepest part of the river channel) as the official border. In return, Iran agreed to cease its support for Kurdish rebels in Iraq. However, after the Iranian Revolution, Saddam Hussein abrogated the Algiers Agreement in September 1980, just days before the full-scale invasion. He declared the entire Shatt al-Arab to be Iraqi territory, effectively reclaiming what he viewed as historical Iraqi rights and signaling his intention to assert full control over the waterway. This act was a clear casus belli and a central territorial motivation behind the Iraqi invasion.

Beyond the Shatt al-Arab, there were also disputes over smaller border territories and islands in the Persian Gulf, but the waterway remained the primary flashpoint, symbolizing sovereignty, economic lifelines, and national pride for both nations.

International Dynamics and Regional Power Plays

The Iran-Iraq War causes were not solely internal or bilateral; they were also heavily influenced by the broader international and regional geopolitical landscape. The Cold War context meant that global powers, particularly the United States and the Soviet Union, viewed the conflict through the lens of their own strategic interests, often providing support to one side or the other, or at least refraining from intervention that might benefit their rival.

Fear of Iranian Revolution's Spread: Many Arab states, particularly the Gulf monarchies, shared Saddam Hussein's fear of the Iranian Revolution's expansion. They viewed Iran's revolutionary ideology as a direct threat to their own secular or monarchical regimes. Consequently, many of these states provided significant financial and logistical support to Iraq throughout the war, effectively backing Saddam as a bulwark against Iranian influence.
Western Concerns: Western powers, led by the United States, were deeply concerned about the stability of oil supplies from the Persian Gulf and the potential for Soviet influence in the region. While initially officially neutral, the U.S. gradually tilted its support towards Iraq, especially after Iran's perceived hostility towards the West (e.g., the hostage crisis). This support included intelligence sharing, financial aid, and later, direct military intervention in the Gulf to protect shipping lanes, primarily from Iranian attacks.
Soviet Ambivalence: The Soviet Union, while having a treaty of friendship with Iraq, also sought to maintain relations with Iran. Their primary concern was preventing either side from becoming too dominant or too aligned with the West. They supplied arms to both sides at various points, albeit more consistently to Iraq, demonstrating a pragmatic approach to regional power dynamics.
Arms Race and Militarization: The decade leading up to the war saw significant militarization in both Iraq and Iran, fueled by oil revenues and regional tensions. Both countries acquired advanced weaponry from various international suppliers, creating a volatile environment where military solutions seemed increasingly viable. This arms race contributed to the confidence of both sides that they could achieve a quick victory, underestimating the opponent's resolve and capacity for prolonged conflict.

These external factors did not directly cause the war, but they certainly exacerbated the existing tensions and, crucially, prolonged the conflict by providing resources and political backing that enabled both sides to continue fighting despite immense losses.

The Devastating Legacy: Consequences and Chemical Weapons

The incredibly deadly and destructive nature of the conflict left a long legacy, including profound human suffering, economic devastation, and lasting geopolitical instability. The war, which lasted for nearly eight years, from September 1980 to August 1988, resulted in an estimated one million casualties on both sides, making it one of the 20th century's deadliest conventional wars. The report details the consequences for both nations, highlighting the immense toll it took on their populations and infrastructure.

The Human and Environmental Toll

Beyond the staggering death toll, millions more were wounded, disabled, or displaced. The war saw extensive use of chemical weapons by Iraq, particularly against Iranian soldiers and Kurdish civilians in northern Iraq (e.g., Halabja). This horrific aspect of the conflict stands as a stark reminder of the brutality unleashed. The environmental consequences were also severe, with oil spills, damaged infrastructure, and scorched earth tactics devastating ecosystems and agricultural lands.

Economically, both nations suffered immensely. Billions of dollars were spent on the war effort, diverting resources from development and leaving both countries heavily indebted. For Iraq, the war's financial burden contributed to its later invasion of Kuwait, setting the stage for the Gulf War in 1990-1991. For Iran, the war solidified the revolutionary government's hold on power, albeit at a tremendous cost in human lives and economic progress. The conflict also fostered a deep sense of national grievance and a determination to develop self-reliance, particularly in military and technological capabilities.

The legacy of the Iran-Iraq War continues to shape regional dynamics, influencing foreign policy, military doctrines, and national identities in both Iran and Iraq, and indeed across the broader Middle East. It remains a painful chapter, a testament to the destructive power of unresolved historical grievances and unbridled ambition.

Lessons Learned: Preventing Future Conflicts

The Iran-Iraq War, born from a complex interplay of historical rivalries, ideological clashes, territorial disputes, and regional power struggles, offers invaluable, albeit grim, lessons for international relations and conflict prevention. Understanding the multifaceted Iran-Iraq War causes is not merely an academic exercise; it is essential for preventing similar catastrophes in the future. The conflict demonstrated the devastating consequences when diplomatic channels fail, when leaders prioritize personal ambition over national well-being, and when external powers inadvertently fuel regional tensions.

Key takeaways include the importance of respecting international borders and agreements, the dangers of ideological expansionism, and the imperative of robust international mechanisms for conflict resolution. The war also underscored the tragic human cost of prolonged warfare and the long-term suffering inflicted by the use of prohibited weapons. While the world continues to grapple with complex geopolitical challenges, the Iran-Iraq War stands as a powerful reminder of the urgent need for dialogue, de-escalation, and a commitment to peaceful coexistence.

The causes of the Iran-Iraq War are a stark reminder of how deeply intertwined history, politics, and ideology can become, leading to devastating consequences. By studying this conflict, we can better understand the complexities of the Middle East and work towards a future where diplomacy prevails over destruction.

What are your thoughts on the primary drivers of this conflict? Share your insights in the comments below, or explore more of our articles on historical conflicts and their lasting impacts.

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