On January 2, 2020, the United States assassinated the commander of the Islamic Revolutionary Guard Corps’ Qods Force, General Qassem Soleimani, in Iraq and accused him of playing a role in an alleged attack on American troops by Iran-backed Shia militias. The assassination signaled a major escalation in the conflict between Iran and the United States. For a moment, the conflict ceased to be a proxy war characterized by efforts to keep tensions deniable and indirect and instead became a direct exchange of violence, with Iran responding to the assassination with a direct missile strike on U.S. forces.

The fallout of the assassination reflects the contradictions and uncertainty at the heart of Iranian proxy warfare strategy and its approach known as “forward defense,”¹ in which Iran seeks to use proxies in other countries to prevent conflict from coming within Iran’s borders. Iran’s strategy was developed over decades through its confrontations with the United States and regional rivals and historically has emphasized its willingness to eschew revisionist religious and ideological aims in order to pursue national interests.

The 2011 Arab Spring, with its threat to Iran’s key partner in Syria while opening opportunities in other areas, inaugurated a more uncertain era for Iran’s proxy strategy. This uncertainty has been heightened by an increasingly aggressive U.S. stance towards Iran. As a result, Iran has played up appeals to religious and ideological aims alongside more traditional forms of proxy mobilization in its forward defense strategy.

Though Iran continues to view and portray itself as pursuing defensive ends vis-à-vis the United States and other rivals, the means it uses tend to signal more revisionist aims, an issue Iranian policymakers recognize as a challenge but embraced anyways. In turn, this has encouraged the United States, and some of its partners, to pursue their own more direct policies of maximum pressure with regard to Iran.

It is far from clear whether Iran can sustainably pursue this strategy. Iran has a history of agile use of proxies and relatively successful navigation between the mobilization of religious and ideological appeals and the pursuit of national interest. However, Iranian society is showing signs of concern regarding the limits of forward defense. Iran’s rivals appear to have assessed that those strains are sufficient and that Iran will fold when confronted.

What is clear, however, is that this uncertainty brings with it the risk of repeated crises with the potential for escalation. Understanding whether and how stability in the relationship can be reasserted will require detailed examinations of the specific balances of national interest, ideological appeals, and Iranian control in the varied national contexts where the conflict is now playing out.

Key Findings:

• The 2011 Arab Spring and 2014 war against ISIS (Islamic State of Iraq and Syria) inaugurated a period of greater Iranian aggressiveness in its use of proxy warfare as it confronted a number of crises that increased Iranian threat perceptions.
• Iranian proxy warfare strategy is shaped by a desire to minimize costs to Iran and its people. As a result, it historically sought to maintain plausible deniability. Iran limited its direct contribution to the defense of the Assad regime in Syria, and has staffed its involvement in proxy wars generally from Islamic Revolutionary Guard Corps (IRGC) volunteers and by mobilizing local or foreign proxies, not by mobilizing the nation’s more general armed forces. Iranian strategists tout the limitations on direct intervention as a success of the strategy.
• While Iran has embraced more aggressive means in the form of a Forward Defense doctrine that seeks to give Iran strategic depth, it still views its objectives as largely defensive. Iran views itself as facing an American threat to its homeland—escalated by the Trump administration’s maximum pressure campaign—as well as an American threat to a key partner in Assad’s Syria, and an ISIS threat to Iranian partners and interests in Iraq.
• However, using proxy forces to wage war on the cheap and as a public deterrent has led Iran to rely upon ideological and religious appeals in order to mobilize fighters and signal its capabilities. In recent years, Iran has grown increasingly bold in making public statements that link together the movements it supports and its influence over their activities.
• Iran’s strategy contains a tension between its proclaimed defensive ends and its offensive means that have signaled a more revisionist intent to Iranian rivals. This tension holds the potential to escalate conflicts and thus make Iran’s strategy unsustainable given its desire to minimize costs. Iranian strategists are aware of the tension but supporters of the forward defense strategy view it as a manageable tension given its history of proxy warfare.
• Iran’s proxy strategy faces real political limits to its sustainability rooted in both domestic anger at the use of funds abroad, economic constraints, and backlash against perceived Iranian domination in countries where Iran seeks to build partners.
• The United States, for its part, has embraced a strategy of maximum pressure that views Iran’s strategy as unsustainable and prone to failure when conflict takes on a more direct character. Through sanctions and direct assassinations of key IRGC personnel, the United States hopes to force Iran to back down.
• It is not clear if Iran’s strategy is actually built to last, but the current moment is likely to be characterized by repeated crises with the potential to escalate into more direct confrontations because Iranian strategists view forward defense as an effective approach agile enough to manage tensions and the United States views it as an unsustainable policy that will fall apart when confronted.
• Policymakers should be aware of the ways in which Iran’s methods of ensuring cost-effective mobilization when pressed shape threat perceptions across the region, the IRGC’s own structure, and Iranian domestic politics. The effects of particular policies are likely to be complex and often unpredictable given the way transnational mobilization and signals interlink conflicts.
• An effective approach to this moment of crisis instability will require analysis of the sustainability of specific Iranian interventions. In some cases, like Iran’s support for Hezbollah, ideological and material ties make it unlikely that pressure can disrupt an established proxy relationship. In others, like Yemen, Iran’s commitment to the Houthis is more vulnerable to pressure. Other cases, like the Shi’a militias in Iraq, are less clear.

The U.S. assassination of Gen. Qassem Soleimani on January 2, 2020 in Baghdad was so unprecedented that many feared that any move afterward might lead to all-out war between the United States and the Islamic Republic of Iran. After four decades of tense rivalry in the Middle East, the American use of an armed drone to target a military official widely viewed as one of the most powerful men in Iran signaled a precipitous climb up the escalation ladder between Washington and Tehran. Iran in turn retaliated on January 8 with direct missile strikes on American forces in Iraq, although the strikes did not kill anyone.² By one account, the Iranians had given the U.S. military an eight-hour notice to clear the bases before the missiles hit. Amir Ali Hajizadeh, head of the Revolutionary Guards’ Aerospace Force, claimed that the warning had been given to the Americans because Tehran “did not intend to kill [persons].”³ Tehran wanted both to show a capacity to strike at the United States but also to demonstrate that it had no intentions to see the military standoff escalate further.

For now, despite the missile strike, Iran appears prepared to double down on the proxy war strategy that was Soleimani’s most significant contribution to Tehran’s anti-access, area denial approach to deterring American attempts to expand U.S. regional influence that could seed regime change in Tehran.

Over the course of the last decade, this Iranian approach to regional military operations began to be described by its proponents in Tehran as “forward defense.” Put simply, forward defense holds that militarily confronting enemies outside of Iran’s borders is preferable to having to face them inside of Iran’s borders. At its core, forward defense is the embodiment of Iran’s military lessons gained over the four decades since the Iranian Revolution of 1979. It reflects a fusion of the tools available to Iranian military leaders combined with the need to address a fast-changing security environment.

While Soleimani was one of the principal creators of the concept, his death will not be the end of the strategy. That has been the message sent by Iran’s Supreme Leader and Commander-in-Chief, Ayatollah Ali Khamenei. Khamenei swiftly appointed Soleimani’s successor, Esmail Ghaani, as head of the Qods Force, the branch of the Islamic Revolutionary Guards Corps (IRGC) that operates outside of Iran’s borders. Khamenei has also been categorical that the mission of the Qods Force as intended by Soleimani will continue. As he put it, “The strategy of the Qods Force will be identical to that during the time of Martyr General Soleimani.”⁴

In a speech on May 22, 2020 set to coincide with Al Qods Day, which is an event to express opposition to the State of Israel, Khamenei was unusually polemical and signaled his determination to stay the course. In urging the expansion of “jihad inside Palestinian territories [Israel],” he not only praised groups such as Lebanon’s Hezbollah, the Palestinian Islamic Jihad, and Hamas but vowed that Iran would stand by them on the path of “holy struggle.”⁵ Iranian officials even set aside the usual application of deniability. In a rare move, state-run media publicized the fact that Soleimani had spearheaded the transfer of Iranian weaponry to Palestinian militants.⁶ Such statements from Tehran are a rebuff of American and Israeli demands that Tehran roll back its support for militant Islamist groups in various theaters in the Middle East.

In pursuing this strategy in the post-Arab Spring era, Iran has increasingly come to embrace aggressive means that involve transnational mobilization and the interlinking of proxy forces, which has in turn encouraged the United States and other Iranian rivals to perceive Iran’s strategy as an offensive and revisionist one.

Soleimani’s assassination, increased tensions vis-à-vis the United States, and the fluidity of the geopolitics of the Middle East, have brought into the open questions in Iran about the long-term costs, benefits, and risks of a forward defense strategy that relies on Tehran’s ability to continue to defy the growing pressures on its economy from U.S. sanctions and fund proxy groups. In the same week as hardliners around Khamenei were touting Tehran’s commitment to militant revolutionary foreign policy, a prominent parliamentarian launched a rare public criticism of Tehran’s regional agenda.

Heshmatollah Falahatpisheh,⁷ who until recently had been head of the Iranian parliament’s committee on national security and foreign policy, asked for Iran to reassess its commitment to the Bashar Al Assad regime in Syria. “[Iran] has probably given 20 to 30 billion dollars to Syria and must recover it. The money belonging to this nation [Iran] has been spent there,” he said.⁸ The reference to funds invested in backing Syria’s Assad was a clear attack on Tehran’s foreign policy priorities or that was at least how Khamenei loyalists viewed it. Hossein Shariatmadari, the Khamenei-appointed editor of Kayhan, the Islamic Republic’s equivalent to the Soviet Pravda, denounced Falahatpisheh as doing Trump’s bidding by turning Iranian public opinion against Tehran’s foreign policy.⁹ The incident was a peek into the opaque policy-making process in Tehran and evidence of competing viewpoints in Tehran in regard to the cost of Iran’s regional efforts and whether it is sustainable.

The question now for the Biden administration and Congress as well as for their counterparts in Iran is whether Iranian proxy war strategy is truly built to last. The Trump administration turned the calculus of indirect confrontation with Iran on its head, evidently deciding that the United States either no longer needs or can no longer afford the risks that come with fighting Iran’s proxies in the shadows. Despite the Trump administration’s repeated public pronouncements that it wanted to reduce the U.S. footprint in the Middle East and discontinue its perceived role as regional policeman, the White House opted to put on display American hard power as a way of forcing the Iranians capitulate to a campaign of “maximum pressure” aimed at forcing Iran to recalibrate its approach to Iraq, Syria, and Israel. This new U.S. approach essentially destroyed the crisis stability that was part and parcel of a covert action strategy anchored in plausible deniability. The high-profile assassination of Soleimani was the most overt expression of this new policy. At the same time, Iran has increasingly adopted public, aggressive means in pursuit of its forward defense strategy.

In the short term, this fresh American resolve will have to contend with one simple reality: Iran’s ongoing determination and ability to mobilize, guide, and launch a host of militant groups across the Middle East that Tehran has painstakingly cultivated for decades. In fact, Soleimani and other architects of Iran’s forward defense, proxy war strategy would argue that this turn in American policy has been long awaited, and that Iran and its allies are ready for the challenge.

Yet, while Tehran’s ability to mobilize an array of foreign militias under its flag is no small feat, the contention that Iran can stay the course regardless of American counter-actions is an untested theory as is the hope of some U.S. policymakers that U.S. pressure can effectively rollback Iranian footprint across the region. Evaluating where, when, and why Iran’s forward defense strategy has worked and where it is built on a sustainable foundation and understanding where it has failed and lacks a sustainable foundation, will be central to determining the effectiveness of both U.S. and Iranian crisis management. In the meantime, the uncertainty will likely bring with it periodic crises that at least appear to hold the potential for further escalation to more direct confrontations.

The rest of this report is divided into three sections. The first section examines the historical development of Iran’s proxy warfare strategy under Soleimani. The second section examines the sustainability of the strategy today, and the third and concluding section draws lessons from the clash between Iranian proxy strategy and America’s new hard power approach.

The geopolitical feud between Iran and the United States dates to 1979 when Ayatollah Ruhollah Khomeini and his militant Islamist supporters overthrew the Shah of Iran and soon after took control of the U.S. embassy. Though many historians have assessed that the CIA-backed coup that led to the ouster of Iran’s Prime Minister Mohammed Mossadegh in 1953 planted the initial seeds of mistrust between the United States and the Iranian people, it was Khomeini’s rise to power that earned the United States its most-hated-nation status in Iran among anti-Shah forces. Following the hostage crisis at the U.S. embassy in Tehran in November 1979, Washington responded in kind, casting the Khomeinists as the source of nearly all wrongdoing in the Middle East.¹⁰

For nearly half a century, the U.S.-Iran conflict was largely characterized by mutual restraint. Neither Washington nor Tehran judged an open military conflict to be in their interests. Instead, a kind of crisis stability anchored in a proxy war paradigm of covert action shaped the normative bounds of American and Iranian strategy. Hit and run attacks on American targets by Hezbollah in Lebanon in the 1980s and later by proxy elements currently allied with the Popular Mobilization Forces or the PMF in Iraq punctuated by American-backed counterattacks in the form of cyber-strikes and targeted assassinations of nuclear scientists on the streets of Tehran have long been part of the backdrop. Each element of this tit-for-tat proxy war between Washington and Tehran always rested on one simple element: plausible deniability.¹¹

Iran’s proxy warfare strategy of using regional non-state militant groups paralleled Qassem Soleimani’s rise as a military commander during the 1990s on the heels of the Iran-Iraq war. Born in 1957, Soleimani came from a poor family in the central province of Kerman. As a teenager he became an anti-Shah Islamist activist before the revolution of 1979 but he did not stand out at that time.¹² The revolution began and prevailed in Tehran but droves of young men—mostly from impoverished rural backgrounds—jumped on the bandwagon. Soleimani was one of them. While he had no formal military training, his chance in life came at the outbreak of the Iran-Iraq War (1980-1988). He enlisted as a volunteer with the Guards and quickly moved up through the ranks of the IRGC, the group of ragtag, armed young men that were empowered and mandated by Ayatollah Khomeini to defend the Islamic Republic against all domestic and foreign enemies.

In late 1980, a few months after the war with Iraq had begun, the 23-year Soleimani was given the command of a volunteer force from his home province of Kerman in what became the 41st Sarallah Division.¹³ This newly formed division was deployed to Iran’s Kurdistan province, an area both known for heavy ethnic Kurdish separatist militancy but also as a staging ground into Iraq. On the other side of the border was Iraqi Kurdistan where Tehran, from the days of the Shah, had cultivated anti-Saddam Iraqi Kurds as allies against Baghdad.¹⁴ It is here that Soleimani experienced first-hand the utility of co-opting and deploying foreign militants as part of military strategizing.¹⁵

Ideological or religious reasons were, at best, secondary drivers at this point. The ideological and religious-based reasoning that later came to dominate the narrative to justify forward defense had yet to be born. Nonetheless, it is during the first years of the Iran-Iraq War, which began in September 1980, that the Qods Force, the expeditionary branch of the IRGC, was born, although its mission would evolve over time.¹⁶ Its actions were centered on cross-border operations along the Iran-Iraq battle lines and on recruiting Iraqis.¹⁷ Mostafa Chamran, an Iranian Islamist revolutionary who had seen military training with Shia militants in Lebanon in the 1970s, was a key driver behind the adoption of asymmetric warfare tactics and became the Islamic Republic’s first defense minister.¹⁸ While Soleimani was not a key player in the formation of this new outfit, he would be a key participant in the application of the new approach, which mirrored the missions of special operations forces in countries like the United States, including covert action and reconnaissance behind enemy lines.¹⁹ In time, what would make the Qods Force stand out was its use of Shia Islamist rallying cries and its recruitment among Shias outside of Iran.

The Qods Force’s mission was not centered on exploiting religious or sectarian fervor at first. The Iraqi Kurds that Iranian commanders like Soleimani collaborated with were not Shia but secular Sunnis. Iranian support for them was an early signal of the Islamic Republic’s willingness to collaborate with an assortment of non-Shia or non-Islamist actors as long as the partnership advanced Iran’s perceived geopolitical interests. In a decade’s time, Iran would be militarily supporting a range of Sunni groups deemed as important to Islamic Republic national interests including the Sunni Afghan Northern Alliance in Afghanistan to the Sunni Bosnians²⁰ in the Yugoslav civil war to the Sunni Hamas in Gaza.²¹ As Zalmay Khalilzad put it in regards to Iran’s modus operandi in Afghanistan during the 1990s, being Shia “was not sufficient to gain Iranian support.”²² This was also evident in Iran’s support for Christian Armenia against Shia Muslim Azerbaijan in the war between the two countries over the disputed territory of Nagorno-Karabakh in the early 1990s.²³

In all of its efforts involving military partners and operations outside of Iran, certain characteristics stand out. Tehran always performed a careful cost-benefit analysis and, as David Menashri argues, it “diligently sought out opportunities in areas, or in movements, that seemed ripe to respond” to its ideological overtures.²⁴ The Shia Islamist Iraqis, many of whom moved to Iran to fight Saddam Hussain’s regime under Ayatollah Khomeini’s spiritual and political leadership during the Iran-Iraq war, were one such group. It was during the early 1980s that some of the most prominent present-day Iraqi militia leaders—men such as Hadi Ameri and Abu Mahdi Al Muhandis, who was killed alongside Soleimani in January—launched their collaboration with their sponsors in the IRGC.²⁵

The Badr Corps, composed of Shia Iraqi Islamists who looked to Iran, began as a brigade and remained under tight IRGC control. This oversight angered Mohammad Baqir Al-Hakim, the Iraqi Shia cleric who headed the political wing of the Badr movement.²⁶ He complained to the then President Ali Khamenei and Speaker of the Majlis, Akbar Hashemi Rafsanjani. Still, the senior IRGC commanders backed by the political leadership in Tehran were determined to maintain strict Iranian control of the foreign forces they were arming and funding. The dispute over command-and-control was somehow resolved and the relationship continued.²⁷ Since the dispute, however, Iran has continued to have lingering doubts about its ability to effectively organize and control its foreign proxies as it sees fit.

Soleimani held the post of commander of the 41st Sarallah Division throughout the Iran-Iraq War. He was one of the youngest military commanders but never a specially celebrated one during the war and his fame would only come years later in the 2000s as he began to cultivate a public image.²⁸ The one factor that appears to have counted in his favor is that he developed a personal bond with the then President Ali Khamenei who frequently visited the war front. The future supreme leader, who took over after Khomeini’s death in June 1989, never forgot that Soleimani had kept him in the highest esteem when many other IRGC commanders viewed Khamenei suspiciously throughout his presidency (1981-1989).²⁹

It was precisely this close personal bond between Khamenei and Soleimani that many analysts have considered as pivotal to the rise and relative independence of the Qods Force during Soleimani’s command from 1998 until his death in 2020. Soleimani’s death thus raised questions about whether the organization would maintain its stature within the power structures of the Islamic Republic without Soleimani at the helm.

After the Iran-Iraq War, Soleimani was given the mission of dealing with rampant organized crime, including arms and drug trafficking coming out of Afghanistan, a country ravaged by civil war where a new breed of extremist movement under the banner of the Taliban was on the rise. Tehran viewed the movement not only as anti-Iran and anti-Shia but as a creation of its regional rivals, Pakistan, Saudi Arabia, and the United Arab Emirates.³⁰

In early 1998, as Iran was still recovering from the devastation wrought by the eight-year war with Saddam Hussein’s Iraq, Soleimani was named head of the Qods Force.³¹ At the time, Soleimani was barely known to the Iranian public, but he was a known figure among warring factions in neighboring Afghanistan where he had served as Iran’s key military liaison to anti-Taliban forces in the Northern Alliance.³² Little analysis has been conducted in the English language about Soleimani’s efforts to aid and guide Northern Alliance forces then under the leadership of Ahmad Shah Massoud, a Sunni and ethnic Tajik leader who was among the top opponents of the Taliban.³³ What is known is that Soleimani had been in his new role less than a year when Taliban forces in August of 1998 captured the northern Afghan city of Mazar-i Sharif and promptly arrested nine diplomats at the Iranian consulate.

The Taliban forces, after they had by one account received instructions from Pakistan’s ISI (Inter-Service Intelligence), killed all the Iranians except one who managed to escape.³⁴ Tehran made a show out of its response, mobilizing tens of thousands of troops on the border ready to go into Afghanistan. Still, after lengthy deliberation, Iran’s Supreme National Security Council (SNSC) opted against a conventional military retaliation against the Taliban, in part fearing being drawn into a quagmire.³⁵ Instead, under the auspices of the Qods Force, Tehran increased its financial and military support for its anti-Taliban partners like Ahmad Shah Massoud.³⁶ Tehran not only welcomed but actively sought to assist the U.S. military campaign against the Taliban in 2001 following the terrorist attacks of September 11.³⁷

Soleimani’s close links with the Northern Alliance would prove enduring and critical for bolstering his assertions about the value of proxy relations for maintaining a forward defense and deterrent against potential aggression or overreach by adversaries. This kind of patronage also gave Iran leverage not just in the military theater but also on the political and diplomatic stages. Foreign Minister Javad Zarif has claimed that the December 2001 Bonn conference that led to Afghanistan’s first post-Taliban government could not have succeeded without Soleimani’s mediation and ability to pressure the various Afghan political groups that he had cultivated ties with throughout the 1990s.³⁸

During the Afghan civil war of the 1990s, the Qods Force and its top commanders, including Soleimani but also Esmail Ghaani, proved to the political leadership in Tehran that the supply of arms and funds to Afghan militants had not only given Iran a say in the battlefield but also had given Tehran a role as a principal powerbroker in that country. This gave Soleimani much personal confidence, which he soon put on public display. By 2008, Soleimani famously sent a message to the top U.S. military official in Iraq: “General Petraeus, you should know that I, Qassem Soleimani, control the policy for Iran with respect to Iraq, Lebanon, Gaza, and Afghanistan.”³⁹

The U.S. invasion of Afghanistan in 2001 and then Iraq in 2003 prompted a period of reorganization and consolidation of Iran’s military expeditionary forces under the Qods Force. Not only did Soleimani have direct access to Khamenei, which meant he could bypass the rest of the IRGC bosses, but the leadership in Tehran had never had more reason to invest in forward defense. In early 2002, the Bush administration named Iran, along with Iraq and North Korea, as part of an “Axis of Evil.” It was not unreasonable for the Iranians to think they might be next in a broader U.S. military campaign in the Middle East following 9/11. Keeping the Americans bogged down elsewhere in the region presented an attractive strategy for Tehran. Despite the risk it took in angering Washington, the strategy was worthwhile if it meant preventing or stalling a possible American attack on the Iranian homeland.

The newly reenergized Qods Force reflected hard lessons learned from several different phases of strategic realignment. From support for Hezbollah in Lebanon beginning in the 1980s to backing for the Northern Alliance in Afghanistan in the 1990s and various groups in Iraq and Yemen in the 2000s, Soleimani’s way of war led to mixed results. Yet, each case allowed Qods Force commanders to adapt and refine their proxy war strategy, and modulate the response to increasing American pressure in the form of covert counter attacks and sanctions. Meanwhile, Soleimani significantly elevated the degree of freedom of operation provided to Qods Force commanders.

As part of the Qods Force organizational structure, each region of operation is given to an individual commander. This “One Country, One File, One Commander” was Soleimani’s brainchild and gives individual Qods Force commanders extraordinary freedom to design and implement policy; but it also makes them responsible for the outcome, according to Morad Veisi, a journalist with Radio Farda, the Iranian branch of the United States’ Radio Free Europe/Radio Liberty and an expert on the IRGC.⁴⁰ In those most delicate theaters where the Qods Force required maximum policy control, its officers have often been the ones Tehran has dispatched as its top diplomatic envoys. In the case of Iraq, all three of Iran’s ambassadors to Baghdad since 2003 have come from the Qods Force.⁴¹

To the Qods Force leaders in Tehran, Iran’s support to a long list of militant groups across the Middle East translates into leverage. These groups are seen as a vindication of the mobilization and financing of the so-called forward defense. The militant groups help to project Iranian military reach and, at times, ideological influence. While Iran’s consolidation of a forward defense strategy was driven by overarching regional dynamics including a growing perception of a U.S. threat and the rise of new opportunities and challenges with the Arab Spring, its character varied across different national contexts. This was so despite growing public references to transnational mobilization and connections between groups.

Hezbollah in Lebanon is the best example of Iran’s forward defense concept.⁴² This should not be surprising. Iran’s own IRGC began as a militia in the aftermath of the Iranian revolution in 1979 and, 41 years later, it is the most formidable political-military-economic actor in the country. This IRGC has diligently worked to replicate its success domestically and turn its foreign proxies into powerbrokers in their respective home countries.

In the case of Hezbollah in Lebanon, the IRGC and its Qods Force foreign branch did not only ideologically indoctrinate and arm the group, but selected and groomed its leaders, including Hassan Nasrallah, its present leader, and Imad Mughniyeh, the group’s top military planner who was assassinated in a joint American-Israeli operation in 2008.⁴³

Hezbollah’s nearly four-decade alliance with the Islamic Republic is the ultimate successful embodiment of the application of forward defense. Unlike many of the other groups that Tehran has backed since 1979, Hezbollah not only shares the Shia Islamist ideological model adopted in Tehran but provides Iran with a platform from which to militarily exert pressure on its top regional nemesis, Israel. From Tehran’s perspective, Hezbollah represents the best the forward defense model can offer: an effective tool of national interest combined with a close and enduring relationship strengthened by both material and ideological ties.

Yet Iran’s military interventions in Syria since the outbreak of the Arab Spring in 2011 demonstrate that ideological conformity is not a prerequisite for Tehran’s support. Hezbollah may be a particularly successful case of forward defense, but it is far from the only model for the strategy, which often relies on proxies whose ideological ties to Iran are often far weaker than those of Hezbollah. The Syrian case also illustrates the limits and risks of Iran’s pursuit of proxy warfare reliant upon relationships of a less enduring and ideologically bound character.

The Islamic Republic has nothing in common in terms of creed with the secular Baathist regime of Bashar Al Assad.⁴⁴ Despite this, Iran intervened militarily on behalf of Assad in close partnership with its ideological offspring, Hezbollah.

Iran’s Syrian intervention demonstrated its versatility. It also showed Iran’s ability to compartmentalize its regional ambitions and work with foreign partners while awkwardly attempting to publicly cast the mission in Islamist clothing. Iran’s key objective was to save a geopolitical ally with a secular system while minimizing costs to Iran itself.⁴⁵ Notably, Iran’s primary foreign cohort in the mission in Syria has been Vladimir Putin’s Russian Federation, hardly a vanguard of Islamism.⁴⁶

The biggest departure in Syria, when compared to the situation in Iraq, was the need for Iran to bring in droves of non-locals—such as Iraqis, Afghans, Pakistanis—to fight under Iranian leadership to keep the Assad regime from collapse.⁴⁷ Unlike in Shia-majority Iraq, where the indoctrination of a generation of pro-Islamic Republic sympathizers had been under way before Saddam’s fall, Syria’s sectarian realities meant that the manpower shortage was a problem for Tehran. This also differentiated Syria from Lebanon, where Iran could rely upon a close ideological ally in Hezbollah. The Qods Force proved agile in circumventing this impediment. In doing so, it sharpened the essence of what forward defense means in practical terms in the post-Arab Spring Middle East by drawing upon transnational networks to resolve the challenges of proxy warfare in a particular context.

The manifestation of forward defense in Iraq and in Syria, since 2003 and 2012 respectively, highlights two basic facts. First, Iran has demonstrated agility in defining and implementing security policy in the region. Second, Iran’s activities in Iraq and Syria reveal a consensus among Iranian policy-makers that the appetite of the Iranian public for forward defense is finite.

Tehran did not engage in large-scale recruitment of Iranians to be dispatched to Syria. The few thousand Iranians sent to Syria, ostensibly as military advisors, were overwhelmingly drawn from volunteers in the ranks of the IRGC and not the conscripted Iranian army.⁴⁸ Iran thus depended upon its ability to appeal to and recruit among non-Iranian Shia in the region in order to mobilize the transnational networks.⁴⁹ While national interest was the primary motivator for Iran’s defense of Syria, the limits imposed by Iranian society required an emphasis upon sectarian and religious appeals in the means of accomplishing those goals.

The mobilization of non-Iranian forces was a double-edged sword. It helped resolve Iran’s manpower problems. But in strengthening appeals to transnational ideological claims, Iran provided its regional rivals with a convincing argument that Tehran was indoctrinating, funding, and arming a new generation of Shia militants and hence, fueling a regional Shia-Sunni sectarian divide. Iran, a non-Arab and Shia majority country with aspirations to lead the Islamic world, has always been highly sensitive to the charge of acting as a Shia sectarian power and it has invested heavily in countering this complaint levelled against it. However, the priority of keeping Assad in power superseded Tehran’s wish to maintain its credibility in the eyes of the Sunni street.⁵⁰ As a result, Iran’s approach helped mobilize opposition to Iranian policy and stoked fears that Iran was seeking more revisionist aims.

The IRGC bosses were undeterred and unapologetic. In August 2012, as Tehran’s military intervention in Syria became increasingly public, then-IRGC Deputy Commander Brigadier General Hossein Salami said “our doctrines are defensive at the level of (grand) strategy, but our strategies and tactics are offensive.”⁵¹ IRGC commanders proudly defended the ability to practice “deep-attack doctrine.”⁵² In April 2019, Khamenei appointed Salami to become the head of the IRGC, and Soleimani’s nominal boss, even as Soleimani retained his direct and much publicized access to the Supreme Leader.⁵³ Meanwhile, Khamenei’s support for forward defense became increasingly overt. “We mustn’t be satisfied with our region. By remaining within our borders, we shouldn’t neglect the threats over our borders. A broad overseas vision, which is the IRGC’s responsibility, is our strategic depth and it is of the utmost importance,” he told the IRGC bosses.⁵⁴

Iran’s role in the Yemeni civil war starting in 2014 demonstrates both the limitations of forward defense war and how Tehran has been selective and careful in applying the strategy. It is commonplace to read that Tehran is the sponsor of the Yemeni Houthi rebels fighting the UN-recognized Yemeni government. In reality, when the last round of conflict began in Yemen in 2014, few Iranians were familiar with the term “Houthis” or “Ansar-Allah,” the official name of the group. The lack of historic ties between Tehran and the Houthi movement and an exaggerated sense of the importance of sectarian bonds between the two only underscore that their relationship has mostly been a marriage of convenience.⁵⁵

Neither Soleimani nor any other senior IRGC commander ever made a public appearance in Yemen. This stands in contrast to prominent public visits to Lebanon, Afghanistan, Iraq, and Syria.⁵⁶ Tehran has not made extensive efforts to spread its religious ideology among the Houthis, who are mostly followers of the Zaidi sect in Islam.⁵⁷ The export of Khomeinism to the Houthis of Yemen has happened, but only in small doses as compared to Iraq or Lebanon. Yemen is, from Tehran’s perspective, too far-flung, too fractured, and unripe to be a good host for Iran’s forward defense doctrine.⁵⁸

Iran has compared the Houthis to Hezbollah in Lebanon.⁵⁹ If the latter could be a spear aimed at Israel, the Houthis could be Tehran’s pawn against the Saudis. Ali Shirazi, Supreme Leader Khamenei’s representative to the Qods force, expressed such a view to the Iranian press in January 2015 and on other occasions.⁶⁰ But Yemen was never a core priority for Tehran and the Houthis were never as submissive to Tehran as Hezbollah or the pro-Iran Shia Iraqi groups. Instead, the dynamic in the Iran-Houthi partnership has depended overwhelmingly on the policy decisions of third-party actors, most notably Saudi Arabia, the United Arab Emirates, and the United States.⁶¹ For example, since late 2019, when the Houthis began the latest round of peace talks with the Saudis and the Americans in Oman, the Iranians were effectively sidelined. The Houthi-Saudi peace talks began shortly after Iran’s Ayatollah Khamenei received a senior Houthi delegation in August.⁶² Either Tehran was urging the Houthis to sue for peace or it had little influence over their strategic decisions (or both). Even in Washington a new message began to be disseminated that downplayed the closeness of Tehran and the Houthis.⁶³

Nevertheless, the Houthis continue to provide Iran with a possible staging-ground from Yemen should Tehran opt to pursue a more militant posture against Riyadh, including via the use of Houthi-controlled Yemeni territory as a launchpad for Iranian-supplied missile strikes. The case of Iran’s relations with the Houthis shows that when examining the extent and appeal of the Iranian proxy model of forward defense, it is critical to look for the depth in relations, which is an indicator of Tehran’s ability to consolidate its regional alliance against the United States and its allies under the banner of the “Axis of Resistance.”

Iran’s forward defense doctrine draws on a long history, including a critical period of consolidation over the 2000s and 2010s. However, as the United States increasingly perceives direct challenges to Iranian proxy actions as a workable strategy, it is far from clear if the doctrine will prove sustainable over the 2020s.

Kayhan Barzegar, a prominent analyst in Tehran on Iranian regional policies, describes Tehran’s logic behind forward defense as “preempting the penetration of symmetric and asymmetric threats inside Iran’s borders.”⁶⁴ According to this line of thinking, Iran not only has to secure its national borders but in certain circumstances it has to go outside of its borders as part of a preemptive national security strategy.

Barzegar calls this the concept of “wider security zone,” which he argues is part of the “the strategic calculus employed by Iranian political-security elites.”⁶⁵ The mastermind behind the concept was Soleimani and, at its core, the logic holds that socio-political turmoil in the region, including the emergence of new security threats such as ISIS, requires an increased and active Iranian response, according to Barzegar.⁶⁶ Others are less certain about the soundness of such logic. Patrick Clawson, director of research at the Washington Institute for Near East Policy, argues the notion of “Soleimani the savior” is highly ironic. According to him, “the Islamic State’s victories in Iraq [after 2014] were largely due to the ultra-sectarian policies he pressed on authorities in Baghdad.” As Clawson puts it, Iran and Soleimani have been both the “fireman and the arsonist,” in regard to conflicts in Iraq and Syria.⁶⁷

What Barzegar calls the application of power in Iran’s wider security zone is merely the latest reincarnation of forward defense. As described above, this concept has evolved over the last 40 years since Iran’s practical military needs during the Iran-Iraq War. It was then that young IRGC commanders like Soleimani looked for ways to overcome Iran’s limitations given Tehran’s isolation and lack of access to conventional military platforms.⁶⁸ Today, the proxy model still reflects Iran’s military weak points but it has also proven its utility.

Since the beginning of the Arab uprisings in 2011, the generals in the IRGC have argued that the shifting regional security environment requires Iran’s military strategy to adapt and reinvent itself. When ISIS carried out its first attacks in Tehran in June 2017, the proponents of forward defense wasted no time in arguing that had Iran not militarily intervened in Syria and Iraq, Iran would have had to confront a far greater ISIS threat inside its borders.⁶⁹ By implication, since the Iranians officially maintain that the United States has been an enabler for the rise of ISIS, Tehran’s rhetorical stance was that fighting ISIS is tantamount to aborting American plans aimed at Iran. As Khamenei put it a few months before the ISIS attacks in Tehran, “there are well-documented news of American aid to ISIS and some other terrorist groups, and now that they [the Americans] have formed an anti-ISIS coalition, some U.S. agencies are still assisting ISIS in other ways.”⁷⁰ With the United States at the heart of Iran’s security calculations, this sort of logic is pervasive in Tehran. Put simply, the fight against ISIS as leverage against the United States is a common theme in the messaging of Iran’s leaders. The Revolutionary Guards Commander, Hossein Salami, explained in September 2019: “In war, the victor is the one that can shape the power equation. No power in the world today, including the United States, has the capacity to wage war against the Iranian people.”⁷¹ Nonetheless, Iranian academics, including those linked to the Foreign Ministry in Tehran, openly publish works admitting that Iran’s rivals do not see Tehran’s military posture as defensive.⁷² By implication, this is an admission that, in the Middle East at least, the concept of forward defense on a large scale is viewed as part of a grand strategy to expand its influence.

For Iran’s regional rivals, the Islamic Republic’s forward defense is considered a case of an ideological commitment rather than an Iranian national security imperative. That Tehran’s reliance on forward defense and depending on foreign militias is mostly by choice, driven by Tehran geopolitical choices and principally its rivalry with the United States and her regional allies. In turn, states such as Saudi Arabia, the United Arab Emirates, and, to a lesser extent, Turkey, are determined to stop Iran in its tracks even as they each are pursuing their own versions of geopolitical forward defense from Yemen to Syria to Libya. As part of this cycle, many billions of dollars are invested in competition for influence in the region.⁷³

The resultant proxy warfare arms races pose a challenge to Iranian strategy, which has sought to minimize costs to the Iranian people. So far, Iran’s forward defense appears largely to have been implemented on a tight budget. Iran is not the biggest military spender in the Middle East today.⁷⁴ But Tehran also has far less cash on hand due to American sanctions. President Hassan Rouhani has claimed that American sanctions have cost Iran $200 billion.⁷⁵ The issue of Iran’s ability to fund its proxy allies, and the reliance of its approach in cases like Syria on stopgap measures that can encourage escalation on the part of its rivals, poses a threat to the sustainability of the forward defense model. However, it is not an imminent risk to Iran’s ability to pursue the strategy.

As Tehran has demonstrated over the years, it is able to prioritize. Not every Arab proxy group has the same value to Iran. Hezbollah of Lebanon is, to a significant extent, politically and religiously indistinguishable from the Islamic Republic. There is, however, much daylight between the Houthis of Yemen and the Iranians. Aside from an ability to prioritize if needed and redefine forward defense depending on circumstances, the Iranian regime as a whole, including the IRGC and its foreign branch the Qods Force, have demonstrated that they are rational actors that engage in a systematic cost-benefit analysis when contemplating military action. Acting rationally does not equate to flawless execution, however. The Iranian military strategy bears the hallmark of trial and error and has proven to be open to mishaps. The Islamic Republic likes to portray itself as a martyrdom-seeking state, but in reality, Iran’s military strategy remains cautious.

Moreover, while the Islamist message has helped Tehran mobilize support in certain pockets in the Arab World, and provided it with a vehicle to expand its regional influence and with Iraq as the best example, excessive attachment to a sectarian agenda can create its own problems for Tehran. The Islamist ruling elite in Tehran is aware of the perils of Iran becoming an entrenched Shia power in an Islamic World where the Shia are a minority and Iran’s Islamist credentials are dwindling. Tehran does not want to feed the narrative that Iran is a Shia sectarian power bent on expanding its influence in Sunni-majority Arab countries.

Meanwhile, as the Islamic Republic faces a deep crisis of legitimacy at home, it is difficult to see how Tehran can stay the course without risking political blowback from an Iranian public that yearns for nation-building at home and an end to costly foreign projects. This anger is nothing new but Soleimani’s assassination, and Washington’s determination to push back against Iranian regional efforts, might give enough reason for the political and military elite in Tehran to rethink the concept and the sustainability of the forward defense doctrine.

In Western analysis, Soleimani is often depicted as a brilliant strategist who exploited chaos in Iraq and Syria to project Iranian power. There is no doubt that he managed before his death to cultivate a warrior image for himself. But Soleimani, and his brothers-in-arms in the IRGC, have come to a critical juncture. Washington has openly warned Soleimani’s successor, Esmail Ghaani, that he too will be assassinated if he opts to follow in the footsteps of his predecessor.⁷⁶

This ultimatum presents the biggest challenge for the Islamists in Tehran and test of the proxy warfare strategy. Forward defense and the use of foreign proxies, such as Hezbollah or the Iraqi militant Shia groups, are today seen by the average public inside Iran and in the broader Middle East as a projection of the ideological zeal of the Islamic Republic and a trend that is depleting Iranian national resources while fueling a costly competition for regional influence with regional rivals. The United States has settled upon a strategy that views this as a sufficient leverage point to enable coercion of Iranian policymakers by moving the conflict towards more direct confrontation.

However, the IRGC appears to view its proxy network, built over four decades, as a sustainable counterweight that can survive such pressure. As a result, the current uncertainty regarding whose assessment of the sustainability of Iran’s proxy strategy is correct is likely to prompt a series of crises in which the U.S.-Iran conflict moves towards direct confrontation as the two sides play a game of chicken. Important to watch across these crises, however, is the extent to which Iran increasingly plays up ideological rhetoric to sustain both transnational and domestic mobilization amid the repeated crises.

Whether or not the mobilization methods are successful in prolonging the sustainability of Iran’s strategy, they will likely play a critical role in shaping the IRGC of the 2020s, just as previous actions shaped today’s IRGC. Those changes bear close monitoring by policymakers and consideration as the United States continues to pursue its strategy of amping up the pressure on Iran as a way to force the leadership in Tehran to reconsider their priorities.