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1. Introduction

Iran has fifteen neighbors, among which undoubtedly Iraq, if not the most important neighbor, is one of its three crucial neighbors, since the geography of Iraq has always been a source of threat against Iran and, in many cases, this threat has had existential dimensions. Over the past 400 years, most wars against Iran have originated from the geography of Iraq. During the Ottoman Empire, in World War I and II, Iran came under attack from the geography of Iraq; the latest instance being the eight-year war considered the longest war of the 20th century. Furthermore, the threat of the Islamic State in Iraq and Syria (ISIS) emerged from within Iraq against Iran.

Iran and Iraq have experienced a century-long period of relations since their establishment, during which the relations between the two countries have gone through various ups and downs. If we consider the relations spanning over a century between the two countries as a spectrum, different forms of relations such as competition, tension, hostility, friendship, war, and so forth have existed along this spectrum. The mentioned forms of relations between the two countries imply that Iran-Iraq relations have not been uniform and have continuously changed, influenced by various conditions and factors.

Since the fall of the Baath Party in 2003 marked a new and completely different chapter for the two countries, this article seeks to investigate the relations between Tehran and Baghdad from 2003 until the time of Shia al-Sudani's premiership in 2022. The goal is to examine the sources that shape and influence Iran-Iraq relations in the mentioned time period and their effect on Iran’s regional influence.

Therefore, the main questions discussed in this article are as follow: Which factors have shaped Iran-Iraq relations in the period from 2003 to 2022?, and what have been the reasons for continuity and change in these elements? This research posits that cooperation between Iran and Iraq was significant until early Haider al-Abadi's tenure, but recent developments have diminished elements of friendship and cooperation, threatening Iran's influence in Iraq. Our hypothesis is that relations affected by the national, regional, and international levels brought positive achievements for Iran, but gradually, and due to the changes made in the three levels of analysis, the Iraqi government has been on the path of critical rethinking of relations with Iran, and the elements of friendship have decreased, which can bring about negative consequences for bilateral relations as well as Iran’s power projection in the region.

2. Methodology

Given the question and hypothesis of this research, both case study and comparative methods are utilized in a historical context and with an analytical approach. The comparative method is beneficial as it allows for the examination of the impact of factors on the three-level analysis of Iran-Iraq relations during the time frame of interest in this study. The historical context is reviewed for examining the developments of the past twenty years to test the hypothesis.

3. Theoretical Framework of the Research

According to the question and hypothesis raised, this study requires a conceptual framework that examines the impact of factors on three levels of analysis (national, regional, and international). In fact, theoretical statements are used with a foundation of analysis based on one of the three levels of analysis. There is no theory without a level of analysis. Therefore, the theories of James Rosenau for the internal level of analysis, the theoretical propositions of Barry Buzan for the regional level of analysis, and the theory of international politics of Kenneth Waltz for the global systemic level of analysis can, in conjunction with each other, help to explain and provide an answer to the problem of this research.

Since the field of international relations encompasses numerous and diverse variables, studying them, especially in relation to each other, can be challenging. Therefore, levels of analysis are utilized for theoretical convenience. These levels of analysis have the advantage of categorizing different factors and units in international relations into separate sections, thus simplifying the complexity of issues (Singer, 1961, p. 77). In practice, although it is not feasible to completely separate the levels of analysis, as they are interconnected and influence each other, in theoretical terms, such separation can be useful for convenience. This article emphasizes the importance of variables at the three levels of national, regional, and international analysis.

The term "national level of analysis" refers to the factors within the political systems of countries that affect their relations with neighbors. In this section, the authors solely focus on examining those internal factors capable of explaining the relations between Iran and Iraq during the specified timeframe. Concepts from James Rosenau’s theory of foreign policy, as well as foreign policy analysis (FPA) are utilized in this part. Variables such as the form and nature of the political system, the position of leaders and their dynamics, bureaucratic politics, and the requirements of the social and cultural environment are examined.

The term "regional analysis" refers to the factors originating from regions such as the Middle East and the Persian Gulf sub-region, which affect the relations between Iran and Iraq. The discussions of regional security complexes such as Barry Buzan's and the Copenhagen School can help clarify the sources stemming from this level that have influenced Iran-Iraq relations.

Additionally, the term "international analysis" refers to the factors that have arisen from the broader international system in a way that directly or indirectly impacts Iran-Iraq relations. The theory of neorealism by Waltz, which focuses on the impact of the international system structure on countries' policies, has been used to explain this aspect.

At the domestic-level analysis, it should be noted that numerous theoretical studies affiliated with either neo-classical realism or liberal schools of thought have been conducted on the impact of political systems on foreign policy. Such studies are based on the assumption that different political systems pursue different foreign policies. This implies that the form and nature of the political system determine the foreign policy and the type of behavior adopted by a country (Farnham, 2004, p. 441). Studies of this kind believe that the foreign policies of authoritarian and democratic political systems differ from each other. The second influential variable on the foreign policy of any country is the role of leaders. James Rosenau considers the role of leaders as one of the five important influential components. In fact, James Rosenau attempts to provide a multi-level (considering both domestic and international levels) and multi-causal explanation of the why and how of foreign policy relying on aggregate and verifiable data (Moshirzadeh, 1396 [2017 A. D.], pp. 138-139). His concept of the individual variable pertains to the role of leaders in foreign policy. Indeed, the unique characteristics of decision-makers and elites are important influential factors in shaping and directing the foreign policies of governments on the international stage. This variable encompasses all aspects of decision-makers and their characteristics, including values, abilities, and past experiences (Rosenau, 1971, p. 108). The influence of individual variables on foreign policy is based on the principle that decision-makers, as individuals possess unique personal characteristics that distinguish their decisions, choices, and foreign policy behaviors from others. Individual variables include personal traits, perceptions, motivations, preferences, leadership styles, decision-making methods, worldview, and decision-makers' belief systems (Dehghani Firouzabadi, 1388 [2009 A. D], p. 70).

Finally, the third theoretical variable is the societal element. In the analysis and understanding of foreign policy, some approaches emphasize the importance of the social-cultural dimension of a country's society and its inevitable influence on domestic policy. For these theoretical approaches to foreign policy, the products of the social-cultural elements within a country are crucial in shaping a nation's identity. The identity imperatives of a country determine what behaviors are permissible or impermissible in foreign policy for statesmen. Therefore, leaders adhere to these identity imperatives because they not only believe in it, but also understand that adhering to these imperatives legitimizes their foreign policy and avoids negative reactions from society (Kiani, 1386 [2007 A.D.], pp. 120-126).

At the regional-level analysis, it should be noted that although for a long time various regional systems were considered as one of the sub-systems of the macro-level analysis, namely the international system, the findings of Buzan and Waever indicate that regions, despite their dependence on and susceptibility to the macro system, have always had a level of independence and followed their own internal dynamics (Buzan & Waever, 2003, p. 75). According to Buzan, the notion of security has a collective nature. This means that the security of countries is interconnected with the security of other countries in the region. Consequently, any developments and changes occurring in the security complex can impact the security of neighboring countries (Buzan, 1991, p. 76). The security complex is defined as a pattern of amity and enmity that constitutes the behavioral norm of a group of states within a particular geographical location and region. This indicates that the patterns of friendly and hostile relations are very similar in various regional security complexes. Additionally, Buzan emphasizes that the regional level of analysis is crucial for explaining many significant regional phenomena and processes. This is due to the fact that the security challenges facing states are often derived from the region's political structures, history, and cultural contexts. The studies of security complexes present a particular methodology, offering a systematic examination of the nature of regional security interactions, including issues of identity, resources, ideology, and power politics.

Lastly, regarding the international level of analysis, Kenneth Waltz emphasizes that the structure of the international system significantly affects the behavior of states and their foreign policy orientations. Waltz posits that the behavior of states in the international arena is largely influenced by the constraints and opportunities presented by the structure of the international system (Waltz, 1979, p. 91). According to Waltz, this structure is defined by the distribution of power and the number of great powers in the system. Furthermore, the structure of the international system determines how states perceive each other and shapes the strategic calculations of their foreign policies (Moshirzadeh, 2020, p. 24).

In conclusion, it should be noted that the tripartite division of analytical levels was merely an act for theoretical convenience in research and study, and in reality, such a division cannot be established.

4. Review of the Developments in Iran-Iraq relations since 2003

With the occurrence of the Islamic Revolution and the overthrow of the Pahlavi regime, a significant turning point occurred in the relations between Iran and Iraq. In the post-Islamic Revolution period, Iran and Iraq experienced various forms of hostility, the eight-year-long war, the economic recession of the 1990s, and so on, which are beyond the scope of this article. This research aims to explain the relations between Iran and Iraq after the fall of Saddam Hussein in 2003, which itself is another significant turning point in the relations between the two countries, based on the theoretical framework proposed.

4.1. Iran-Iraq Relations from 2003 to 2022 in the Light of National Level Analysis

This section demonstrates how three factors have influenced the relations between Iran and Iraq during the mentioned time period, leading to changes and continuity in relations between these countries: the structure and nature of the political systems in Iran and Iraq, the leaders of both countries, and the dynamics of Iranian and Iraqi societies.

4.1.1. The Structure and Nature of the Political Systems in Iran and Iraq

The political structure of Iran is characterized by a unique and intricate governance system that intertwines theocratic and republican elements. Established in the wake of the 1979 Islamic Revolution, the Islamic Republic of Iran operates under the principle of velayat-e faqih, or guardianship of the Islamic jurist, which positions the Supreme Leader as the ultimate authority in the political hierarchy (Alaaldin, 2020). This central figure wields considerable power over all branches of the government, embedding religious oversight within the state's functions. The Supreme Leader's authority extends over critical institutions, including the military, the judiciary, and media outlets, while the President and the Parliament (Majles) also play significant roles in governance. Iran's political structure has remained largely stable, allowing for a continuity of foreign policy objectives, particularly in relation to Iraq. The concept of "resistance" has been a cornerstone of Iran's regional policy, framing its interactions with Iraq and other regional actors.

In stark contrast, Iraq's political system has undergone profound transformations since the fall of Saddam Hussein’s Baath regime in 2003. The establishment of a democratic government, primarily influenced by Shia parties, has significantly altered the dynamics of Iran-Iraq relations. The rise of a Shia-centric political order in Iraq was initially met with approval from Iranian leaders, who viewed the new regime as an opportunity to expand their influence in the region (Young, 2019). The emergence of political entities such as the Supreme Islamic Council of Iraq (SIIC) and Al-Dawa Party, which historically sought alignment with Iranian interests, has allowed Iran to cultivate strong ties with key Iraqi political figures. The role of shared religious values, especially those rooted in Shiite traditions, emerged as a soft power tool in Iran-Iraq relations (Amirzadeh et al., 1395 [2016 A.D.]). This shared religious identity has been strategically used to bolster diplomatic relations and foster a sense of transnational Shiite solidarity.

However, as Iraq has evolved politically, the initial alignment has given way to increasing complexity. The introduction of a multi-ethnic and multi-sectarian democratic framework, enshrined in the 2005 Iraqi Constitution, has created an environment where various factions, particularly Shia, Sunni, and Kurdish groups, compete for political power and representation (Knights, 2023). Iraq’s federal structure has presented both opportunities and challenges for maintaining a cohesive national policy, affecting its interactions with regional powers like Iran. Budaghi et al. (1400 [2021 A.D.]) explore the historical evolution and future implications of federalism in Iraq, shedding light on the ways in which internal divisions impact foreign relations and regional stability. This fragmentation has often hampered the establishment of a cohesive national identity, and has resulted in a precarious balance of power among these groups, leading to heightened tensions and rivalries that complicate Iraq's foreign policy orientation.

While Iran has sought to leverage its relationships with Shia factions in Iraq to enhance its regional influence, the rise of Iraqi nationalism and the assertiveness of leaders advocating for greater autonomy from Tehran have introduced new challenges to this relationship. The political fragmentation has culminated in growing public skepticism towards Iranian involvement in Iraqi affairs, particularly as segments of the Iraqi population express concerns regarding sovereignty and the potential for foreign domination (Gholami & Ahmadian, 1393 [2014 A.D.]).

Additionally, the political dynamics in Iraq have been further complicated by the role of external actors. The presence of American military forces in Iraq, particularly following the U.S. invasion in 2003, has created a counterbalancing force against Iranian influence (Blanchard & Humud, 2016). The U.S. has strategically aligned itself with various Iraqi factions, including Sunni and Kurdish groups, which has facilitated a competing narrative that emphasizes the importance of Iraqi sovereignty and independence from foreign influence.

In summary, the political systems of Iran and Iraq, while deeply intertwined due to historical and cultural ties, remain markedly distinct in their governance structures. Iran’s political system maintains a firm grip on power through its religious leadership and ideological commitments, while Iraq's democratic-like framework is marked by its ethnic and sectarian complexities. As these political structures continue to evolve, the interplay between them will significantly shape the trajectory of Iran-Iraq relations, influencing both regional stability and the balance of power in the broader Middle East.

4.1.2. The Role of Leaders in the Relations between the Two Countries

During the specified period, the leaders of Iran and Iraq significantly influenced the trajectory of their bilateral relationship. In Iran, four presidents held office—Mohammad Khatami, Mahmoud Ahmadinejad, Hassan Rouhani, and Ebrahim Raisi—yet it was the Quds Force, operating under the auspices of the Supreme Leader, that predominantly directed Iran's foreign policy in the Middle East. The Quds Force plays a critical role in shaping Iran-Iraq relations, functioning as a key instrument of the Iranian leadership’s regional strategy.

The position of the Supreme Leader within the constitutional framework of the Islamic Republic of Iran has been pivotal in ensuring political stability, particularly in the volatile context of the Middle East. The Supreme Leader's perspective and directives have played a significant role in influencing Iran-Iraq relations during this period. Following the events of 2003, the Supreme Leader's ideological core has centered around the concept of the Axis of Resistance. Although the Axis of Resistance was initially conceived in the 1990s in response to the peace processes between certain Arab states and Israel, it gained enhanced prominence in Iraq after the fall of Saddam Hussein and, particularly, in the aftermath of the Arab Spring and the subsequent domestic war in Syria. The Axis is a regional integration of resistance forces, who fight against US domination and Zionist expansion in the Middle East (Anderson, 2020).

The Supreme Leader, through the command of the Quds Force and the Ministry of Foreign Affairs, has directed Iran's foreign policy in the region, emphasizing resistance against perceived threats from Israel and the United States. This strategic orientation facilitated Iran’s active engagement in Iraqi affairs following the U.S. occupation in 2003. Iran deployed the Badr Organization and played a central role in establishing the Supreme Council for the Islamic Revolution in Iraq to enhance its influence within the country. By fostering unity among Iraqi Shia factions and promoting cooperation between Shia and Kurdish groups, Iran sought to contribute to political coherence in Iraq during critical electoral periods, notably in 2005, 2010, 2014, and 2018.

The significance of Iran's involvement in Iraqi political developments became particularly evident following the 2014 parliamentary elections and the subsequent territorial advances of the ISIS. Amidst rising tensions and the failure to form a stable government in Iraq, several Shia and Kurdish factions expressed opposition to Nouri al-Maliki's continued premiership. In this context, Iran’s leadership played a mediating role and facilitated al-Maliki's withdrawal from candidacy, paving the way for Haider al-Abadi to assume the position of Prime Minister. The visible presence of the Popular Mobilization Forces during the war against the ISIS served as a testament to Iran's strategic management of its influence and its acceptance by significant Iraqi factions. However, after the defeat of the ISIS, Iraq faced severe economic problems, leading to dissatisfaction and protests among the Iraqi people. Opposing groups accused the PMF of violently suppressing the protests. Additionally, Iraqi protesters blamed the political system of the Islamic Republic of Iran, as the supporter of the PMF, for Iraq's problems (Knights et al., 2023).

The landscape shifted after 2018 with the emergence of independent political figures and the assassination of key Iranian and Iraqi military leaders, General Qasem Soleimani and Abu Mahdi al-Muhandis. These events have posed serious challenges to Iran's political influence in Iraq, signaling a potential decline in Tehran's ability to project power and assert its interests in the face of evolving Iraqi political dynamics (Knights, 2020; Azizi, 2021).

Given that the Iraqi prime minister is primarily responsible for the country's executive branch, examining the role of Iraqi prime ministers after 2005 is necessary to understand Iran-Iraq relations. Each of these prime ministers had a particular perspective on Iran, which influenced the Iran-Iraq relationship.

Ibrahim al-Jaafari, the first prime minister of Iraq, was closely aligned with Iran, being fully supportive of the Islamic Republic due to Iraq's nascent and weak position in 2005. Therefore, during his tenure, the foundation for a good relationship with Iran was established. In 2006, Nouri al-Maliki, a prominent figure from the Islamic Dawa Party, ascended to the premiership of Iraq. His tenure, extending until 2014, was characterized by a notably close alignment with Iran, surpassing even the ties previously established by his predecessor.

Al-Maliki exerted considerable pressure on the Mujahedin-e Khalq Organization, which had established a significant presence in Iraq since the Iran-Iraq War, effectively compelling them to vacate their bases. This maneuver facilitated the collaboration of Iranian forces with Iraqi troops at Camp Ashraf, thereby augmenting Iranian operational capabilities within Iraq's borders (Barzegar, 2007). However, the extent of al-Maliki’s closeness to Iran provoked substantial unease among various Iraqi factions. Kurdish factions, particularly the Democratic Party of Kurdistan, began to shift their allegiances toward Turkey, while Sunni Arab factions sought closer ties with both Turkey and Saudi Arabia. This pivot was indicative of a broader apprehension regarding Iran's burgeoning influence, perceived as a threat to Iraq’s sovereignty and national interests (Gholami & Ahmadian, 1393 [2014 A.D.]).

Following the parliamentary elections in 2014, Iraqi factions coalesced around Haider al-Abadi as a consensus candidate, regarded as a more moderate figure, less beholden to Iranian dominance. Al-Abadi’s premiership, which lasted from 2014 to 2018, coincided with the rise of the ISIS and the subsequent establishment of the Popular Mobilization Forces (PMF). These developments presented formidable challenges to his administration after the military defeat of the ISIS in 2017. In response, Iraqi leaders began to actively reclaim sovereignty and counterbalance the power that had tilted towards the PMF and Iranian-affiliated security forces within the Iraqi security apparatus (Blanchard & Humud, 2016).

To counteract the influence of Shia ideological forces and Iranian-affiliated entities, Abadi undertook strategic initiatives aimed at reintegrating senior commanders from the counter-terrorism institution into other security and military structures. His objective was to gradually reform these institutions, which had been infiltrated by Iranian interests, by instilling a more balanced and nationalistic perspective within their ranks (Aldroubi, 2018). The Badr Organization, which had historically dominated the Iraqi Ministry of Interior, epitomized the type of entity that Abadi sought to reform.

Essentially, al-Abadi endeavored to either dissolve the PMF or subordinate it under the jurisdiction of the Iraqi government and armed forces. His strategic vision aimed at maintaining Baghdad's neutrality amid escalating tensions between Tehran and Washington, thereby articulating his coalition's goal as the establishment of an "independent and stable Iraq" (Hasan, 2017).

After the 2018 elections, Adel Abdul Mahdi was appointed as Iraq's fourth Prime Minister, presenting a leadership style that was more aligned with Iran compared to al-Abadi. However, following public protests in November 2019, Abdul Mahdi was compelled to resign, paving the way for Mustafa al-Kadhimi, who was officially designated as Prime Minister on April 19, 2020 (31 Farvardin 1399). Al-Kadhimi’s ascendance was notable, as he emerged as a nationalist figure and represented a significant shift in Iraq's political landscape; he was the first Prime Minister post-Saddam Hussein who did not originate from a political Islam background, thus reflecting a departure from previous trends (Makiya, 2020).

As an intelligence official with a secular background and nationalist inclinations, al-Kadhimi sought to implement reforms within the Iraqi political framework. Unlike his predecessors, who had been selected from the Islamic Dawa party, al-Kadhimi’s premiership marked a critical turning point in Iraq's political trajectory (Rubin, (. He emphasized a policy of independent action that prioritized the preservation of Iraq's national sovereignty in its dealings with Tehran. Al-Kadhimi has been vocally critical of the extensive cooperation exhibited by earlier governments with Iran. In a poignant critique of Nouri al-Maliki’s administration, he asserted in 2013, “Only a strong and cohesive Iraq that secures Iraq's interests will exist, and this will not happen unless Baghdad shows its neighbors that it is not merely Iran's backyard” (Abdulla, 2020). Throughout his tenure, he advocated for engagements with Iraq's governmental framework and insisted that interactions be conducted through formal diplomatic channels. Notably, he ordered the removal of a memorial plaque commemorating Soleimani at the site of his assassination, further signaling his commitment to reducing Iranian influence within Iraqi affairs (Abdulla, 2020).

Al-Kadhimi's advocacy for independence from Iranian influence extended beyond rhetoric; he took substantive steps to fortify Iraq's sovereignty. He restructured his cabinet to reinforce Iraq's autonomy, appointing General Osman al-Ghanimi as Minister of Interior—an individual trained by American forces. This appointment was particularly significant, as the Ministry of Interior had historically been dominated by elements associated with the Badr Organization. Furthermore, al-Kadhimi reinstated Abdul-Wahab al-Saadi as the commander of the Counter-Terrorism Service, an entity regarded as America's most trusted military force in combating terrorism in recent years (Halawa, 2020). He also appointed General Abdul Amir Rashid Yarallah as the Chief of Staff of the Joint Chiefs of Staff, who had collaborated closely with U.S. forces during the Mosul campaign in 2016-2017 (Institute for the Study of War, 2020).

In the realm of foreign affairs, he selected Fuad Hussein as the Minister of Foreign Affairs. Hussein, an experienced Kurdish politician, was a proponent of the U.S. presence in Iraq and aimed to fortify relations between Iraq and the United States. Additionally, al-Kadhimi appointed Ali Abdul Amir Allawi as Minister of Finance, who promoted reducing Iraq's economic dependence on Tehran, particularly within the energy sector.

In conclusion, while the Islamic Republic of Iran has historically played a significant role in Iraq and exerted considerable influence over its political landscape, efforts to mitigate this influence have gained momentum since 2014 through the actions of various Iraqi Prime Ministers and bolstered by support from Kurdish and Sunni factions. These endeavors have yielded varying degrees of success in limiting Iran’s sway in Iraq. As Iraq continues to navigate its complex political landscape, Iranian leaders have had to adapt to shifts in Iraqi governance, particularly with figures like Mustafa al-Kadhimi at the helm. Dagher (2020) notes that while Kadhimi’s rise was cautiously accepted by Tehran, his emphasis on sovereignty and closer ties with Western allies adds tension to Iran-Iraq relations, indicating a nuanced approach from Iran as it recalibrates its influence. A salient point supporting this assertion comes from General Kenneth McKenzie, former commander of U.S. Central Command (CENTCOM) from 2019 to 2022. In his book, The Melting Point: High Command and War in the 21^st Century, McKenzie explicitly asserts that if Qasem Soleimani had been alive, Mustafa al-Kadhimi would not have ascended to the premiership of Iraq. He interprets the electoral victory of the Sadrist movement as a notable setback for Iran, attributing this development to the absence of pivotal figures such as Soleimani and Abu Mahdi al-Muhandis. McKenzie further elucidates the reduction of Iranian influence in Iraq (McKenzie, 2024).

4.1.3. The Societal Factors in Bilateral Relations

The societal dynamics between Iran and Iraq have been central to shaping their bilateral relations, influencing both political engagements and cultural connections. With both countries sharing a predominantly Shia Muslim population, these religious demographics have historically provided a foundation for closer ties. However, these societal linkages also present challenges, as sectarian divides, ethnic affiliations, and nationalist movements often complicate the diplomatic landscape.

One of the most significant societal ties between Iran and Iraq is the shared religious identity of Shia Islam, which has long served as a critical bridge between the two nations. Shared Shiite values play a significant role in shaping Iran and Iraq’s bilateral relations, especially in public diplomacy efforts. Amirzadeh et al. (1395 [2016 A.D.]) highlight the way in which these values serve not only as cultural connectors, but also as instruments for strategic influence, contributing to mutual support frameworks that strengthen diplomatic relations. Through shared religious principles, both countries leverage these values to foster solidarity and alignment on socio-political issues, effectively utilizing cultural and religious diplomacy to bridge potential divides. The religious seminaries in Qom, Iran, and Najaf, Iraq, have cultivated enduring ties that facilitate religious exchanges, including the movement of clerics and students across borders. Pilgrimages to Najaf and Karbala during events such as Arbaeen bring millions of Iranian pilgrims to Iraq each year, strengthening cultural and religious bonds. These gatherings serve as an avenue for Iran to exert influence by fostering solidarity within the Shia communities of Iraq (Blanchard & Humud, 2016; Barzegar, 2007).

However, societal developments in Iraq, especially post-2003, have complicated Iran's influence. Initially, after Saddam Hussein's fall, many Iraqi Shia welcomed Iran's role in their political and social spheres, particularly given the religious affinity. However, over time, nationalist movements within Iraq, especially among the younger generation, have become wary of Iran's involvement. The 2019 anti-Iran protests revealed a shift in public opinion, particularly among Iraqis who view Iran’s influence as a threat to their sovereignty (Young, 2019; Al-Rubaie, 2019). The severe crackdown on Iraqi protests, as documented by Loveluck and Salim (2019), underscored the internal volatility that complicates Iraq’s foreign relations, particularly with Iran, given that some protests directly opposed perceived Iranian interference. This rising nationalist sentiment is increasingly critical of foreign interference, highlighting the complexities of societal factors in Iran-Iraq relations.

Ethnic and sectarian divides within Iraq also play a significant role in shaping specific societal attitudes towards Iran. While Iraq’s Shia majority, particularly in the southern regions, has generally been more receptive to Iranian influence, the Sunni minority and Kurdish populations remain skeptical of Tehran’s intentions. Sunni Arabs, who feel marginalized by the Shia-dominated government and its ties to Iran, have looked to regional actors such as Saudi Arabia and Turkey for support. The evolving attitudes of Iraqi Sunnis toward the U.S. presence reflect deeper concerns about increasing Iranian influence in Iraq. According to Freeman (2020), Iraq’s Sunni population, once resistant to American influence, now seeks U.S. support as a means to counterbalance Iran’s growing presence, underscoring the shifting priorities within Iraq’s internal politics. Similarly, Kurdish groups, especially in the Kurdistan Region of Iraq, have maintained a cautious approach towards Iran, often favoring relations with the U.S. and Turkey over Tehran (Gholami & Ahmadian, 1393 [2014 A.D.]; Knights, 2023).

Cultural exchanges between Iran and Iraq have also played a pivotal role in shaping bilateral relations. Iran has invested heavily in promoting cultural diplomacy, establishing media outlets, and sponsoring joint cultural events in Iraq to promote its soft power. These cultural initiatives aim to reinforce Iran's image as a protector of Shia interests in Iraq. However, they are met with resistance from Iraqi nationalist factions, who view them as part of a broader strategy of ideological expansion (Hasan, 2017; Amwaj Media, 2022).

In recent years, social media and digital platforms have further complicated the societal landscape. The rise of social media has enabled both pro-Iranian and anti-Iranian voices to gain traction, with platforms amplifying nationalist sentiments that challenge Iran’s influence. Social media has become a space for Iraqis to express frustration with perceived foreign interference, with movements like the 2019 protests galvanized online (Alaaldin, 2019; Hasan, 2019). These dynamics underscore the importance of societal factors in shaping the future of Iran-Iraq relations.

In conclusion, societal factors in the relationship between Iran and Iraq are both a source of cooperation and tension. While religious and cultural ties have historically facilitated engagement, growing nationalist and anti-Iranian sentiments in Iraq, along with ethnic and sectarian divides, have increasingly complicated the relationship. As societal dynamics continue to evolve, they will remain a crucial factor in determining the trajectory of bilateral relations.

4.2. The Relations between Iran and Iraq in Light of Regional Dynamics

The regional dynamics of the Middle East, characterized by shifting alliances and strategic rivalries, have significantly impacted the trajectory of Iran-Iraq relations. Since the 2003 U.S. invasion of Iraq and the subsequent downfall of Saddam Hussein’s regime, Iran has sought to capitalize on the political vacuum in Iraq to extend its regional influence. However, Iraq’s strategic location, caught between competing regional powers such as Saudi Arabia, Turkey, and the broader Arab world, has meant that Iran’s ambitions have consistently faced challenges from regional actors.

Iran’s post-2003 strategy in Iraq has been shaped by a broader regional vision, wherein Tehran seeks to position itself as a dominant power in the Persian Gulf and beyond. In particular, Iran has employed what it refers to as the Axis of Resistance, a strategic alignment with non-state actors and regional governments opposed to U.S. influence, Israel, and Sunni Arab hegemony (N. Pour Esmaeili, Personal Communication, 2021; Anderson, 2020). Iraq’s Shia-led government has been a key partner in this axis, with Iran backing political factions and militias that align with its regional ambitions (Barzegar, 2007). This alignment has allowed Iran to project power into Iraq, influencing both its domestic politics and its security landscape, particularly through organizations such as the Popular Mobilization Forces (PMF). Iran's involvement in Iraq reflects a broader strategy aimed at countering rival influences in the region, particularly from the United States and its allies. According to the International Crisis Group (2005), Iran’s approach is multifaceted, involving political support, economic ties, and, at times, direct involvement in Iraq’s security sector.

At the same time, regional actors such as Saudi Arabia and Turkey have viewed Iran’s growing influence in Iraq with alarm, seeing it as a direct threat to their own regional interests. Saudi Arabia, in particular, has worked to counterbalance Iran’s influence by supporting Iraq’s Sunni Arab communities, hoping to limit Iran’s sway over the Iraqi state. Riyadh’s involvement in Iraq has intensified following the rise of the ISIS, as the Saudi government has sought to expand its presence in Iraqi politics by offering aid and investment to Sunni regions (Young, 2019). This has created a regional environment in which Iraq is increasingly caught between the competing agendas of Tehran and Riyadh.

Turkey, meanwhile, has pursued its own interests in Iraq, particularly regarding the Kurdish question. Ankara has maintained close relations with the Kurdistan Regional Government (KRG) in northern Iraq, viewing the KRG as a counterweight to both Baghdad’s central government and Iranian influence. The shared concerns between Turkey and the KRG over Kurdish autonomy in Syria and the activities of the Kurdistan Workers' Party (PKK) have fostered an alignment between Turkey and the Iraqi Kurds, further complicating Iran’s ability to project influence in the region (Gholami & Ahmadian, 1393 [2014 A.D.]).

The geopolitical dynamics of the broader Arab world have also influenced Iran-Iraq relations. Since the Arab Spring, which began in 2011, the Middle East has experienced increased instability and shifting alliances. The regional power vacuum, coupled with sectarian tensions, has deepened the rivalry between Iran and Saudi Arabia, with Iraq frequently becoming a battleground for influence. Iran has leveraged its support for Shia militias and political parties in Iraq as part of its broader strategy to counter Saudi influence across the region. These militias have not only played a central role in the fight against the ISIS, but have also been integrated into Iraq’s security apparatus, further cementing Iran’s foothold in the country (Blanchard & Humud, 2016).

The regional competition has also manifested in Iraq’s relationships with the Gulf Cooperation Council (GCC) countries, particularly Saudi Arabia and the UAE. These Gulf states have sought to reintegrate Iraq into the Arab fold, viewing this as a means of curbing Iran’s influence. Since 2017, there have been notable efforts by Gulf states to improve relations with Baghdad, including high-level diplomatic exchanges and economic investments in southern Iraq. Despite these efforts, Iraq’s political elites, particularly those aligned with Iran, have remained wary of closer ties with the GCC, concerned that such alliances could undermine their relationship with Tehran (Amwaj Media, 2022).

Moreover, the involvement of the United States in the region continues to be a crucial factor in the Iran-Iraq relationship. Since the U.S. invasion of Iraq, Washington has maintained a significant military presence in the country, often acting as a counterbalance to Iranian influence. The U.S. policy in Iraq has focused on strengthening the central government, combating terrorism, and reducing the influence of Iranian-backed militias (McKenzie, 2024). However, the U.S. presence has also been a point of contention between Baghdad and Tehran, with Iran viewing it as an obstacle to its strategic ambitions in the region. This has led to a complex trilateral dynamic, with Iraq often caught in the middle of competing U.S. and Iranian agendas.

In conclusion, regional dynamics have profoundly shaped the relationship between Iran and Iraq, with both countries navigating a landscape of competing regional powers, sectarian divides, and external pressures. Iran’s attempts to cement its influence in Iraq through the Axis of Resistance have been met with resistance from Saudi Arabia, Turkey, and the Gulf states, all of whom seek to limit Tehran’s power in the region. That also includes Israel which has growing concern regarding the influence of Iranian-backed forces in the region (Waxman, 2009). As Iraq continues to develop its post-ISIS political and security frameworks, its ability to balance these competing influences will be critical in shaping the future of Iran-Iraq relations.

4.3. Iran-Iraq Relations in the Light of International System Analysis

The relationship between Iran and Iraq has been profoundly influenced by the evolving international system, particularly in the post-Cold War era. The interplay of global power structures, shifting alliances, and geopolitical competition has shaped the way in which both countries navigate their foreign policies within the broader framework of the international order. Iran’s perspective on Iraq and its subsequent policies can be better understood when examined through the framework of the international and belief systems. Daheshyar (1383 [2003 A.D.]) argues that Iran's approach to Iraq is shaped by a combination of systemic pressures and ideological imperatives, which influence its stance toward both regional neighbors and global powers. Since the 2003 U.S. invasion of Iraq, the dynamics of the international system have increasingly centered around American hegemony, the rise of multipolarity, and the strategic positioning of key regional powers. This section explores how Iran-Iraq relations have been shaped by these global forces.

One of the most critical factors in understanding Iran-Iraq relations within the context of international system analysis is the neorealist theory, particularly as articulated by Kenneth Waltz. According to neorealism, the international system is defined by the distribution of power among states, which leads to the formation of alliances, balances of power, and hegemonic struggles. In this framework, the U.S. invasion of Iraq in 2003 disrupted the regional balance of power, effectively removing a key counterweight to Iranian influence and allowing Tehran to expand its strategic footprint in Iraq (Waltz, 1979). The collapse of the Ba'athist regime created a vacuum that Iran was quick to fill, utilizing both soft power through religious and cultural ties and hard power via political and military influence, especially through the deployment of the Quds Force and support for various Iraqi Shia militias (Blanchard & Humud, 2016).

The broader U.S. strategy in the Middle East, characterized by efforts to establish a liberal democratic order in Iraq, inadvertently enabled Iran to increase its influence. The power vacuum that followed the removal of Saddam Hussein allowed Iran to extend its regional influence, particularly by aligning with Shia political groups and militias within Iraq. From an international system perspective, Iran’s behavior can be understood as a rational response to U.S. power projection in the region. By cultivating allies in Iraq, Tehran sought to establish a buffer against American dominance and secure its interests in the Persian Gulf (Barzegar, 2007).

In contrast, the U.S. policy of containment towards Iran, particularly during the George W. Bush and Obama administrations, aimed to limit Tehran’s influence in Iraq by fostering a strong central government in Baghdad and supporting rival Sunni and Kurdish factions. However, the inability of the U.S. to fully stabilize Iraq after the withdrawal of American forces in 2011 allowed Iran to further consolidate its position. Under President Trump, U.S.-Iran tensions in Iraq intensified, peaking in 2020. That summer, the U.S. claimed Iran-backed groups threatened American interests, reducing its forces over fears of embassy attacks. Events culminated with the assassination of Soleimani and al-Muhandis, leading Iran to retaliate by striking the U.S. Ain al-Assad base. The strategic rivalry between the U.S. and Iran has thus been a defining feature of Iran-Iraq relations in the context of international system analysis, with both powers seeking to influence the future trajectory of Iraq’s political and security landscape (Blanchard & Humud, 2016). The international system has also been characterized by a gradual shift towards multipolarity, with emerging powers like China and Russia playing an increasingly prominent role in the Middle East. For Iran, cultivating relations with non-Western powers has become an essential component of its foreign policy strategy. Russia’s intervention in the Syrian civil war and its broader partnership with Iran in countering U.S. influence in the region has had implications for Iraq as well. Both Tehran and Moscow share an interest in limiting American hegemony, and their cooperation has strengthened Iran’s position in Iraq, particularly through their support for the Assad regime in Syria, which has direct security implications for Baghdad (Kozhanov, 2017).

Moreover, China’s growing economic and diplomatic presence in the Middle East has influenced Iran’s approach to its relations with Iraq. As China deepens its engagement in Iraq through infrastructure projects and energy investments as part of its Belt and Road Initiative (BRI), Tehran sees an opportunity to enhance its own economic influence. Iran has sought to leverage Chinese involvement in Iraq to counterbalance U.S. economic sanctions and Western isolation. This alignment within the international system reflects Iran’s broader strategy of seeking multipolar partnerships to offset Western dominance, particularly in Iraq, where U.S. influence remains a critical concern (Scobell, 2020).

The rise of non-state actors and transnational threats, such as the ISIS, also plays a significant role in shaping Iran-Iraq relations within the international system. The global response to ISIS’s territorial expansion, which saw unprecedented international cooperation, including the U.S.-led coalition’s military intervention and Iran’s support for the Popular Mobilization Forces (PMF), highlights the ways in which non-state actors influence state behavior in an increasingly interconnected international system. Iran’s role in combating the ISIS in Iraq allowed it to position itself as an essential security partner, not only within Iraq, but also within the broader international community. This engagement further solidified Iran’s influence in Iraq while challenging the U.S. narrative of Tehran as a destabilizing force in the region (Gholami & Ahmadian, 1393 [2014 A.D.]). Notwithstanding, the rise of the ISIS also created a reason for the U.S. to re-engage in Iraq, challenging Iran's power. Forming a coalition of over 60 countries, the U.S. played a central role in ISIS's defeat, prioritizing stability through non-military initiatives (Mossallanejad, 2016). President Obama's focus was on curbing the ISIS ideology without direct force. The U.S. return, with Iraqi and Kurdish support, enabled it to curb Iran’s maneuvering.

In conclusion, Iran-Iraq relations cannot be fully understood without situating them within the broader framework of international system analysis. The U.S.-Iran strategic rivalry, the rise of multipolarity, the involvement of non-state actors, and the growing influence of powers like Russia and China have all played a pivotal role in shaping the bilateral dynamics between Iran and Iraq. As the international system continues to evolve, the balance of power in Iraq will remain a central concern for both regional and global actors, with Iran seeking to maintain its influence in a rapidly changing global order.

5. Analysis of the Consequences for Iran’s Policy towards Iraq:

As previously mentioned, the Iran-Iraq relations during the timeframe of this article can be divided into two periods, each with specific results and consequences for the Islamic Republic of Iran.

5.1. Period of Intimate Interaction and Cooperation

During this period, which extends until the early tenure of Prime Minister Haider al-Abadi and the defeat of the ISIS in 2017, influenced by the specific conditions at three levels of analysis, as described, the relations between the two countries were in a favorable situation, resulting in the following positive outcomes for Iran's interests and security:

1. A Shia-centric political system emerged in Iraq that relied on assistance and support from the Islamic Republic of Iran. This situation meant that Iraq became the first country in the region to have friendly relations with Iran.
2. The Islamic Republic of Iran managed to put an end to the presence of the Mujahedin-e Khalq Organization, its largest military opposition group, through Iraq. It also restricted the activities of Iranian Kurdish armed groups in Iraq.
3. During this period, Iraqi Kurds and Iraqi Shia stood together, with Iran playing a mediating and conciliatory role between them, which enhanced the credibility of the Islamic Republic of Iran.
4. Interactions and friendship between the Iranian and Iraqi communities increased during significant events like Arbaeen. Iranians traveled to religious sites in Iraq, and Iraq became a significant destination for pilgrimages, tourism, education, healthcare, etc.
5. Iraq's alignment with Iran led to the elevation of Iran's regional role and power.
6. The grounding of American military forces in Iraq and their subsequent withdrawal in 2011 were positive steps for Iran's security.

Despite the above positive outcomes for Iran's interests and security, other developments occurred that did not yield positive results for Iran:

1. The Islamic Republic of Iran abandoned the Sunni community in Iraq. This factor led to the Sunni community in Iraq becoming a serious challenge for Nouri al-Maliki's government after the US withdrawal from Iraq and eventually forming the nuclei of the ISIS in Iraq. This, in turn, led the Sunni community in Iraq to seek external allies such as Saudi Arabia and Turkey.
2. The Maliki government’s crackdown on the Kurdistan Region and efforts to dissolve its pre-Maliki autonomy led the Kurdistan Democratic Party of Iraq to distance itself from Iran as a supporter of Maliki and move towards Turkey and the United States.
3. Relying solely on a portion of Iraq's Shia population and disregarding the rest led individuals like Ayad Allawi to accuse the Baghdad government of being dependent on Iran, gradually fueling public sentiments against Tehran in Iraq.

5.2. Period of Iraq's Critical View of Relations with Iran

The accusation of the Iraqi government's dependency on the Islamic Republic of Iran led to the gradual emergence of individuals and political figures in the Iraqi political arena who held a critical view of relations with Iran and pursued the policy of preserving Iraq's independence. This situation resulted in the following negative consequences for Iran's interests and security:

1. Shia forces supported by Iran, with the Hashd al-Shaabi as their nucleus, came under internal pressures within Iraq and international pressures. Domestically, the government sought to limit their influence, while externally, they faced sanctions from the United States and sometimes assassination attempts. Iran's reliance on a specific segment of Shia led to protests from other Shia factions, such as Muqtada al-Sadr.
2. A consensus and convergence arose among the opposing currents to Tehran and the Baghdad government, such as the Kurdistan Democratic Party, Sunni factions, and certain Shia factions. The continuity of this convergence would make the future Iraqi governments stronger against Iran (Personal Interview with former foreign minister Javad Zarif, 2024).
3. Influenced by the approach of political currents critical of Tehran, a significant portion of the Iraqi society moved towards adopting a critical view of the Islamic Republic of Iran and distanced itself from Iranians, compared to the enthusiasm of previous years.
4. The dominance of a military-security approach towards Iraq led to significant stagnation in Iran's commercial and economic relations, opening up opportunities for Iran's competitors (Personal interviews with Javad Zarif & Abbas Araghchi, 2024).
5. Iraq adopted a policy of balance in the region and sought to expand its interaction with Iran's rivals in various dimensions.
6. From 2014 onwards, not only did American military forces return to Iraq, but the country also entered into strategic collaborations with the United States. The U.S.-Iraq Strategic Dialogue emphasizes a commitment to strengthen bilateral relations and enhance cooperation on various fronts, including security and economic development (U.S. Department of State, 2021).

In general, it can be argued that the current relations between Iran and Iraq are characterized by instability and rupture, which are expected to intensify in the future.

6. Conclusion

This article has explored the intricate relationship between Iran and Iraq, emphasizing the multifaceted factors that have shaped their interactions since the fall of Saddam Hussein’s regime in 2003. The analysis underscores the significance of historical ties, societal dynamics, regional influences, and the broader international system in understanding the evolving nature of bilateral relations.

The societal factors, particularly the shared religious identity of Shia Islam, have historically served as a foundation for cooperation between Iran and Iraq. However, the rise of nationalist sentiments within Iraq, coupled with the emergence of anti-Iran protests, indicate a shift in public opinion that challenges Tehran's influence. While cultural and religious connections continue to bind the two nations, increasing calls for Iraqi sovereignty reflect a growing desire to resist foreign interference, especially from Iran.

In the context of regional dynamics, Iran's post-2003 strategy has leveraged the power vacuum created by the U.S. invasion to expand its influence in Iraq. However, this expansion has been met with resistance from regional powers such as Saudi Arabia and Turkey, who perceive Iran's actions as a threat to their own national interests. As Iraq navigates its complex geopolitical landscape, the interplay between these regional actors will remain crucial in determining the future of Iran-Iraq relations.

Furthermore, the analysis within the framework of international system theory reveals the way in which global power dynamics shape bilateral interactions. The U.S. strategic rivalry with Iran, the rise of multipolarity, and the involvement of non-state actors such as the ISIS highlight the complex factors influencing Iraq’s foreign policy decisions. The ongoing competition between Tehran and Washington, coupled with the increasing engagement of emerging powers like China and Russia, suggests that Iraq will continue to be a focal point for both regional and international players.

In conclusion, as Iran and Iraq confront an evolving political and security environment, the nature of their relationship will be shaped by internal dynamics, regional rivalries, and the broader international context. Future developments in Iraq’s political landscape and its relations with external powers will significantly impact the trajectory of Iran-Iraq relations, requiring continuous scrutiny of these interconnected factors.