Keywords

1 Introduction

Syria today stands at the crossroads of regional and international geopolitical currents. The Arab uprisings of 2010–11 and the ensuing instability that shook the Syrian regime have created a strategic battleground for regional dominance and Great Power contestation.Footnote 1 In the seventh year of the war, the conflict shows no sign of drawing to an end, but instead has entered a new stage. This phase is seeing a shift away from proxy war and an increasing risk of direct interstate clashes, with a real possibility of confrontations involving Israel, Iran, Turkey, Russia and the United States.

The partnership between Syria and Iran stretches back over four decades, and the bond between these two very different states raises an important research question for the field. What is propelling this enduring alliance in a region known for its dizzying array of constantly shifting partnerships? Many initially believed the alliance would be short-lived, tied as it had been to exigencies facing Iran and Syria during the Iran–Iraq War,Footnote 2 or that it would not be strategically significant or durable owing to ‘underlying incompatibilities in their respective interests and aspirations and in the political ideologies underpinning the structure of their respective governments and societies’.Footnote 3 These ideological differences—between Syria as a secular pan-Arabist state and Iran as a theocratic pan-Islamist power—were considered too fundamental to allow for any genuine long-term partnership even over shared geopolitical interests.

Nevertheless, in fact the partnership has not only endured but deepened over time. The reasons for this endurance lie largely in geopolitical factors and shared threat perceptions.Footnote 4 Iran and Syria are drawn together by their opposition to the US-led regional security order, and this alliance reflects the desire of ‘middle powers’ to ‘defend their autonomy against intensive Western penetration of the Middle East’.Footnote 5 These shared concerns explain how Syria and Iran were able to transcend their ideological differences to work towards shared visions of regional autonomy and reduced foreign penetration of the Middle East.

In recent years, especially since 2011, Iran has demonstrated its strong commitment to its ally and has been a major player in the Syrian conflict. Iran has consistently supported the Syrian government by sending military advisers to the country, establishing transnational militias there and providing political support in the international arena. Yet many mainstream analyses, which are largely divorced from theoretical frameworks, interpret Iran’s actions as expansionist,Footnote 6 reflecting an attempt to recreate the Persian Empire,Footnote 7 by means including the creation of a land bridge from the Iranian plateau to the Mediterranean Sea.Footnote 8 Others analyse Iranian behaviour through a sectarian lens, focusing on Iran as a predominant Shi’a power,Footnote 9 or on Iranian anti-Israeli ideology.Footnote 10

Many of these accounts, however, downplay or ignore Iranian security concerns and misread Iranian behaviour owing to an inadequate understanding of Iranian threat perceptions and strategic planning. There are exceptions. Some scholars have analysed Iranian strategy in the Syrian war through the prism of Tehran’s security concerns.Footnote 11 Others have framed Syrian and Iranian foreign policies as a means of increasing regime resilience at home by using ‘foreign policy to acquire nationalist legitimacy from external threat’—an approach in which resistance to outside threats from actors such as the United States and Israel is used to legitimize centralization of power and popular mobilization for the regime at home.Footnote 12

However, the limited periods covered by these works mean that they do not account for the full evolution of Iran’s strategy throughout the Syrian war. In this chapter, we focus specifically on the drivers of Iranian foreign policy towards Syria over a period of decades, but especially since 2011. We argue that the most salient factor driving Iran’s relationship with Syria—from the Islamic Revolution to the current Syrian conflict—has always been a strategy of deterrence. While Syria may be important for Iran for other reasons as well, such as enabling it to undertake counter-containment, the fundamental basis of the relationship is first and foremost deterrence; this can explain Iranian actions throughout the course of the Syrian war. Syria offers Iran vital strategic depth in the Arab world, allowing it manoeuvrability throughout the Levant, and provides it with a gateway to Hezbollah, enhancing Iranian deterrence of Israel. Yet, just as the development of the Iran–Syria relationship began before the formation of Hezbollah, so continued strategic cooperation between the two countries demonstrates that the relationship now represents an independent axis.

This chapter contributes to the debates on Iranian strategy and regional geopolitics by explicating the primacy that deterrence has consistently played in determining Iran’s Syria strategy, as opposed to other ideological, geopolitical or sectarian factors. It draws on a rich array of primary source materials in Arabic and Persian, with key references to speeches by leaders of Iran, Syria and Hezbollah, and builds on insights and experience gained through extensive fieldwork in Iran and Lebanon. It also provides an analysis, hitherto largely absent from the field, of the stages and drivers of Iranian behaviour since the beginning of the Syrian conflict in 2011.

We begin by discussing how deterrence has underwritten the nature of Iran–Syria ties since the 1979 Islamic Revolution. We then examine the debates on Syria within Tehran at the onset of the Syrian conflict. Next, we focus on the different phases of Iranian decision-making during the war, explaining why Iran shifted from a localized strategy of supporting the Syrian regime to regionalizing and internationalizing the military coalition. Finally, we look at Iran’s Syria strategy following the defeat of the Islamic State in Iraq and Syria (ISIS) and the emergence of rivalry among multiple stakeholders in the country, above all Russia, Turkey and the United States, alongside their respective allies.Footnote 13

2 The Logic of the Relationship

Deterrence is the underlying logic that has bound Iran and Syria together from the beginning of the Islamic Revolution in 1979 up to the present day. Syria was the second country to formally recognize the Islamic Republic and assisted Iran during the eight-year long Iran–Iraq War (1980–1988). The Syrians also trained Iranians in ballistic missile technology, and the two countries coordinated support for non-state actors, including Hezbollah and Palestinian resistance organizations, against Israel and the United States in the Levant. Deterrence continued to be the primary driver deepening the alliance in the new century, notably after the 2003 Iraq War when the United States established a military presence in Iraq between the two countries. On the basis of their convergent interests, the relationship between Iran and Syria can be divided into three periods: first, the formative stage of cooperation in the 1980s based on mutual threat perceptions; second, a cooling of relations as strategic incentives diverged during the Gulf War and throughout the 1990s; and third, the renewal and consolidation of the strategic alliance within what is referred to as the Axis of Resistance following the 2003 Iraq War and in a context of heightened security threats.

Deterrence implies a strategy to prevent hostile actions through shaping the cost–benefit calculations of adversaries, specifically to prove that ‘the costs and/or risks of a given course of action [an adversary] might take outweigh its benefits’.Footnote 14 Deterrence theory is therefore concerned with the imprecise science of estimating an enemy’s intentions and seeking to influence them.Footnote 15 Establishing credibility is foundational to the enterprise of achieving deterrence, and the primary focus of the literature therefore rests upon the various means by which states issue ‘conditional threats’ and demonstrate the credible ‘prospect of punishment’ in order to shape behaviour.Footnote 16

Deterrence theory has largely developed in the United States and accordingly reflects western strategic thinking during the Cold War, with much less attention given to deterrence strategy as practised by countries in the developing world.Footnote 17 Accordingly, much of the literature involves a strong focus on nuclear deterrence and the noteworthy role that highly destructive weapons such as the nuclear bomb have had in determining deterrence strategy, especially during the Cold War.Footnote 18 However, other work has also focused on conventional deterrence, or deterrence undertaken with conventional weapons,Footnote 19 and there is a growing literature on asymmetric deterrence involving non-state actors.Footnote 20 Nevertheless, the field has not resolved whether the concept of deterrence is of universal application across the full range of states and non-state organizations, and is still struggling to address the general criticisms of the theory, including the claim that deterrence does not work well and is a poor strategy in practice.Footnote 21 One critical case in which deterrence actually does seem to hold, demonstrating the concept’s continued relevance and significance, is that of Israel and Hezbollah since the 2006 war.Footnote 22

Beyond the challenge posed by a dearth of theoretical work on deterrence in non-western settings, the difficulty of understanding Iranian behaviour also stems from the fact that the country’s strategy is built on combined conventional and asymmetric deterrence that also incorporates the support of other state and non-state actors, all of which introduce considerable ambiguity in terms of effective messaging, rational decision-making, and establishing credible capability without nuclear deterrence.Footnote 23 Iran’s conventional deterrence capabilities are largely rooted in its domestic ballistic missile programme and its capacity to use missiles to hit regional targets, as demonstrated in strikes in Iraqi Kurdistan and on ISIS positions in Syria in September and October 2018 respectively. Iran also has asymmetrical deterrence capabilities largely through its support of regional non-state actors, such as Hezbollah in Lebanon, and also through the operational activities of the external branch of the Islamic Revolutionary Guards Corps (IRGC), the Quds Force.

In this chapter, we seek to shed light on the importance Iranian strategists give to deterrence and demonstrate how this concept shapes the country’s objectives in Syria. Specifically, we argue that Iranian strategy within the Levant, including both Syria and Lebanon, should be understood as ‘forward deterrence’. Here we define forward deterrence as the deployment or possession of deterrent capacity beyond one’s own national borders that abut on the adversary’s frontier. Iran’s forward deterrence strategy has not historically involved direct forward deployment of armed forces, since its deterrence capacity is largely provided by partners and allies that are not under formal Iranian control. In other words, while Iran has a conventional deterrence strategy—as evidenced by its ballistic missile programme—in parallel it also has a forward deterrence strategy in the Levant via Syria and allied non-state actors. Syria therefore provides Iran with strategic depth in the Levant and access to Hezbollah, while Syria itself also has a combined conventional and asymmetric deterrence strategy against Israel. These are all different components of what Iran terms its ‘comprehensive deterrence’ (bazdarandegi-e hame janebe) doctrine, according to which it uses diverse and multi-layered means to defend itself from any potential aggression.

Iranian and Syrian threat perceptions have been shaped from the beginning of their relationship by a shared sense of regional isolation and a shared antiimperialist ideology.Footnote 24 The two countries forged a partnership with the practical objective of deterring regional threats from their main adversaries. These were primarily the United States, Israel, and Iraq under the regime of Saddam Hussein.Footnote 25 In particular, the Iran–Iraq War brought about a convergence of threat perceptions as Iran and Syria both perceived Iraq as a common enemy. The alliance also came at a critical juncture for Syria, which in March 1979 lost Egypt as an ally with the signature of the Camp David Accords making peace with Israel.Footnote 26 Further, Iran and Syria are both staunch supporters of the Palestinian cause: Syria was and is the home of many Palestinian groups, including the Popular Front for the Liberation of Palestine (PFLP), which has historically been headquartered in Damascus, and in the 1980s and 1990s Syria extended support to Islamist groups including Hamas and Islamic Jihad.Footnote 27

On the Iranian side, symbolizing the country’s firm stand against Israel, the ‘first Palestinian embassy in the Middle East’ was opened on the grounds of the vacated Israeli mission in Tehran following the Islamic Revolution.Footnote 28 More importantly, both Syria and Iran considered their patronage of Palestinian groups as part of an effective deterrence against Israel. Joint training activities were carried out for the PFLP in Lebanon’s Beqaa valley on the eve of the Arab Spring by Hezbollah, overseen by Iran, with a reported 4,000 highly trained PFLP fighters hosted in a military base in Qusayra, Lebanon.Footnote 29 For Syria, the Iranian Revolution was a godsend: Hafez al-Assad viewed the previous Israeli–Iranian alliance as representing a stranglehold over the Arab world, interpreting the Shah’s support for Iraqi Kurdish insurgents as a means of bogging down Iraq and preventing it from providing support for a united Arab front against Israel.

Following the Islamic Revolution, the Iranians felt both isolated regionally and under threat from the United States, Tehran’s primary adversary. This was a stark change from the pre-revolutionary period, when Iran and the United States were close allies and Iran sold oil to Israel in exchange for training its military personnel there, and Iran’s notorious SAVAK intelligence services were trained by both the CIA and Israel’s Mossad.Footnote 30 Revolutionary Iran’s realignment away from a pro-western axis was in large part a result of significant historical grievances against the West held by Iranians, including the Anglo-Iranian oil crisis and coup d’état against Mohammad Mossadegh in 1953 and other significant humiliating territorial and economic concessions exacted from Iran by western powers since the nineteenth century.Footnote 31 Iran’s assumption of a regionalist and anti-imperialist approach in defining its Middle Eastern priorities and threat perceptions overlapped with Hafez al-Assad’s vision of rejecting the interference of extra regional powers in the domestic affairs of the region.

In parallel to developments in revolutionary Iran, Syria faced increased regional isolation for two reasons. The first was as a consequence of the Camp David Accords of 1979.Footnote 32 Despite Egypt’s decision to discontinue conflict with Israel, the Syrian regime demonstrated continued populist and pan-Arab zeal, ironically alienating it from much of the Arab world. The second, a point of increasing concern for Syria, was in regard to Iraq. Syria needed to preserve its position vis-à-vis Iraq for both ideological and geopolitical reasons. As countries both ruled by Ba’athist parties that simultaneously claimed the leadership of the Arab world, they were locked in an intense rivalry that threatened their respective domestic and regional political legitimacies and created the conditions for potential conflict.Footnote 33

Geopolitically, Syria also sensed increased vulnerability as Iraq’s influence grew regionally after the fall of the Shah and with Arab support for Iraq’s efforts in the war against Iran. Accordingly, a logic of deterrence and balancing the existential Iraqi threat during the Iran–Iraq War shaped the foundation of the Iran–Syria partnership.Footnote 34 The collaboration, rooted in the 1979 Revolution, was a pragmatic strategy designed to mitigate the two countries’ shared vulnerability and isolation, and to overcome the threats posed by Iraq.Footnote 35

The third perceived shared threat was from Israel. While Hafez al-Assad was careful to try not to antagonize the United States, Syria’s continued opposition towards Israel served as a wedge preventing any meaningful rapprochement with America, especially in the context of the pre-Arab Spring Middle East.Footnote 36 Located at the front line of the Arab–Israeli conflict and as a ‘self-proclaimed’ leader of Arab nationalism,Footnote 37 Syria had always considered Israel a significant threat. However, this became all the more important following the Camp David peace accords and the Israeli invasion of Lebanon in 1982, both events prompting Syria to look for a partner that could support it against a common enemy. While the Camp David peace accords deprived Syria of Egypt as an ally against Israel, Israel’s invasion of Lebanon led directly to the emergence of a new partner for Syria: Hezbollah.

The important point here is that Hezbollah served as an extension of Iran’s Islamic Revolution and a reflection of its anti-Zionist ideology, even though its creation was prompted by factors independent of Tehran, namely the Israeli occupation of southern Lebanon.Footnote 38 This structural opening led to an opportunity for Iran’s policy of ‘export[ing] the revolution’ in the 1980s.Footnote 39 Accordingly, the Iranian–Syrian partnership converged behind Hezbollah against a common enemy. On top of ideological factors, Iran also considered Israel a military threat because of its close alliance with the United States. Iran thus saw in Hezbollah an opportunity to project deterrence and leverage against the United States in Lebanon, including the taking of American hostages and potentially targeting the American military presence in that country.Footnote 40 In this way Hezbollah would provide Iran with deterrent capability via its targeting of Israel and US interests in the Levant. Eventually, while the export of revolution lost primacy after the first decade of the Islamic Republic, the deterrent logic behind Iran–Hezbollah ties remained, and remains, strategically significant.

In the 1990s, the Iran–Syria partnership weakened as mutual threats diminished and the impetus for deterrence decreased. Iran pursued a more pragmatic foreign policy following the end of the Iran–Iraq War and the arrival in power of more moderate presidents, Hashemi Rafsanjani (1989–96) and the reformist Mohammad Khatami (1997–2004). Both administrations wanted to normalize Iran’s regional and international standing and thus sought detente with the United States.Footnote 41

Despite Iran’s status as an anti-American revolutionary state, Rafsanjani made great efforts to invite the US oil company Conoco to do business in the country, only to be surprised by President Bill Clinton’s blocking it through an executive order in March 1995, which was followed one month later by a ban on all US trade and investment with Iran. Later, Congress passed a ‘sweeping sanctions bill, later signed by Clinton, to punish foreign companies that invested $40 million or more in the oil resources of Iran’.Footnote 42

This move was all the more significant as in 1993 US exports to Iran amounted to US$1 billion and the United States was the largest purchaser of Iranian oil in the early 1990s, taking around 30 per cent of Iran’s oil exports with a total value of over US$4 billion.Footnote 43 Despite the American measures, Iran pursued detente with Saudi Arabia and greatly improved its relations with the Arab states of the Persian Gulf during this period. A major meeting of the Organization of Islamic Cooperation was hosted in Tehran in 1997 and was attended by Crown Prince Abdullah and the Saudi Foreign Minister; King Fahd even donated cloth from the Ka’ba to be displayed at the summit.Footnote 44 Hezbollah also moved to normalize its relations in the domestic context of Lebanon, setting aside its more revolutionary ideals and pursuing pragmatic goals as a legitimate party in the Lebanese political scene.

Thus during these years its value for Iran and Syria declined as it gained greater autonomy and independence from its patrons. At the same time, Syria saw Iraq as less of a threat after the 1991 Gulf War, during and after which—much to Iran’s dismay—it cooperated with the United States. This brought Syria closer to other Arab countries, which viewed Saddam Hussein as a common enemy after his invasion of Kuwait. Also indicative of a drift in Syrian–Iranian relations was Syria’s decision to enter into negotiations with Israel in the late 1990s.Footnote 45 Thus a divergence of interests and a weakening of the logic of deterrence based on mutual threats diminished cooperation between Iran and Syria and marked a slackening of the relationship during the 1990s. After 2003, however, a series of strategic reversals forced Syria closer to Iran again. With the American invasion of Iraq, a much more direct threat emerged from the United States. The establishment of a permanent and hostile US presence on the border of both countries galvanized further strategic cooperation and coalition-building in order to ensure survival. The Axis of Resistance was thus born to fend off shared threats. This became all the more important for Syria following its expulsion from Lebanon after the 2005 Cedar Revolution, which added to Damascus’s sense of increased insecurity. The forces pushing Syria and Iran together culminated in the 2006 Israel–Hezbollah war, which demonstrated the potential for shared resistance and joint military effectiveness.

Thus the Iran–Syria alliance deepened as threat perceptions converged and intensified. Eventually, with the outbreak of the Syrian war in 2011, the relationship became even stronger. As the historical trend line demonstrates, the weaker Syria becomes, the more its strategic alignment with Iran advances.

3 Iranians Debate Syria

The Iran–Syria relationship faced its most pressing challenge with the onset of the Arab Spring. The mass protests that rocked the Arab world in 2010–11 reached Syria in March of the latter year, later than in other states of the region. Although the Syrian government employed tactics of both repression and appeasement, the protests continued unabated.Footnote 46 Faced with this growing challenge, the Iranian foreign policy establishment became embroiled in an unprecedented internal debate on its position regarding Syria, a key Iranian ally and a critical actor in the Axis of Resistance, with divergent narratives taking shape around the Syrian protests. This contrasted with Iran’s immediate adoption of a clear position on the regional uprisings as a whole, which it hailed as an ‘Islamic Awakening’ modelled on its own revolutionary success.Footnote 47 The debate in foreign policy circles, like many others within the Islamic Republic,Footnote 48 in part reflects the relative openness to discussion of divergent policy positions among a ruling elite used to competitive elections within the framework of a hybrid political system that mixes democratic and non-democratic regime features,Footnote 49 and the factional penchant for politicizing issues for purposes of domestic gain and elite rivalry. While national security policies are generally arrived at through consensus in the Supreme National Security Council, there is a relatively permissive approach to debate during the process of deliberation. Moreover, the Supreme Leader initially did not enforce one clear position, thus enabling different branches of government, such as the President, members of parliament, the heads of state institutions and political factions, to take divergent positions on the subject of Syria.

Two different discourses emerged within the Iranian political elite on the Syrian uprising, and these—contrary to many analysesFootnote 50—transcended political and factional dividing lines. The first was the Arab Spring approach: a call for the support of all popular uprisings against ossified dictatorships reminiscent of Iran’s struggles against the Shah. Adherents of this normative framing argued that Iran should support the legitimate demands of the Syrian people as it did those in other Arab countries, fuel the ‘Islamic Awakening’, and put pressure on its own ally to allow political reform. Conservative President Mahmoud Ahmadinejad, for example, supported this approach, claiming that ‘we should not pay more costs in Syria because the time of Bashar Assad is over’.Footnote 51 In a controversial speech, Hashemi Rafsanjani, the moderate head of Iran’s Expediency Council, took a similar position, criticizing the Syrian regime and highlighting the atrocities committed against the Syrian people.Footnote 52

Within the Arab Spring framework, others took a more recent episode as their frame of reference for assessing the Syrian protests. The green movement protests following the 2009 elections and the alleged fraud leading to the re-election of Ahmadinejad had produced the largest mass protests since the 1979 Revolution. Many viewed the Arab Spring protests as mirroring their recent struggle. As Mir Hossein Mousavi, the reformist presidential candidate and a leader of the green movement, stated: ‘The starting point of what we are now witnessing on the streets of Tunis, Sanaa, Cairo, Alexandria, and Suez can be undoubtedly traced back to . . . when people took to the streets of Tehran in the millions shouting “Where is my vote?”’Footnote 53

The second narrative framed the uprising through a geopolitical lens and focused on the impact of the Syrian crisis on the regional balance of power. This narrative treated the Syrian uprising as a foreign plan to overthrow a key ally on the front line of the Axis of Resistance and thus tilt the balance of power against Iran.Footnote 54 This was supposedly an attempt to offset the gains Iran had made in particular since the 2003 Iraq War, the 2006 Israeli–Hezbollah war and the toppling in 2011 of pro-US secular dictatorships in Egypt, Tunisia and Yemen that had been hostile towards Iran. From this perspective, fomenters of the Syrian crisis were aiming to roll back Iranian gains and cripple Iran’s deterrent capabilities against Israel and the United States. On this view, the potential collapse of Assad and the loss of its main Arab ally would have been a critical blow to Iran’s regional interests. Many Iranian strategists deemed it necessary to take active measures to counter this threat. Among them was Brigadier-General Hossein Hamidani, the commanding IRGC general in Syria, who in urging this course referred to Saudi offers of support to Damascus if it cut ties with Iran in exchange.Footnote 55 General Qasim Sulaymani, head of the IRGC Quds Force, pointed to Riyadh’s unsuccessful attempts at turning Assad against Iran, claiming that King Abdullah told Assad that ‘Lebanon is yours’ if he were to abandon Iran.Footnote 56 Assad later confirmed these offers in a public interview.Footnote 57 An analysis published on Ayatollah Ali Khamenei’s website also illustrates this position: Westerners considered the Syrian opposition as an opportunity to limit Hezbollah and cut relations between Iran and Syria, and they tried to eliminate the contact between Iran and Syria and destroy Iran’s supportive bridge to Hezbollah through the toppling of Bashar Assad, thus putting Hezbollah under pressure.Footnote 58

In explaining Iran’s support for the Syrian regime later in the conflict, Sulaymani pointed to the fact that Syria had been the only Arab country to stand by Iran during the Iran–Iraq War when all other Arab countries opposed Tehran.Footnote 59 He added that if Iran had not entered the conflict, ‘ISIS and the al-Nusra Front would have established a government in Syria and . . . dominated the region.’Footnote 60 He further alluded to Syria’s anti-Israel position: In the face of all the countries that established private or public contacts with the Zionist regime, only one country, Syria, was willing to sacrifice its security and all of its territory for Muslims. And even during the time of President Bill Clinton when the issue of peace between Syria and the Zionist regime was supposed to be resolved in Paris, Hafez Assad went to Paris but did not attend the morning session and was not present at the negotiation because he knew what the impact of Syria’s compromising over the steadfastness of the Resistance front against Israel was and as a result he thwarted it.Footnote 61

While this anti-Israeli stance might be perceived as catering to domestic audiences in Iran or even aimed at appealing to widespread anti-Israeli sentiments in the region, in reality Iran has worked extensively to counter Israel on the ground. Evidence of this can be seen in Iran’s logistical support for Hezbollah from its inception in 1982, when it fought against the Israeli occupation of Lebanon, and during later significant crises such as the Israeli–Hezbollah war of 2006. It can also be seen in Iran’s backing of Hamas (especially its military wing) in Palestine, and its support of Palestinian Islamic Jihad, as well as other geopolitical alliances aimed at countering Israeli threats, including, of course, its 40-year-old alliance with Syria which has been defined by its emphasis on forward deterrence against Israel.

According to this view, Tehran could not turn a blind eye to the regional push against Assad as Iran considered itself the party under threat in Syria. A prominent Iranian cleric made the claim that ‘if we lose Syria, we will not be able to preserve Tehran’.Footnote 62 The reformist Rear-Admiral Ali Shamkhani, who currently heads Iran’s Supreme National Security Council, claimed that Iranian involvement in Syria prevented the crisis from spilling over into Iran.Footnote 63 Over time, this perspective has been reasserted both by Iran and by its allies in the region. Referring to Iranian soldiers killed in Syria and Iraq, the Supreme Leader declared in early 2016 that Iranians who departed to fight ISIS ‘went to battle an enemy that would have entered the country if they had not fought them [abroad] . . . [otherwise] we would have had to battle them here in Kermanshah and Hamedan and the rest of Iran’s provinces’.Footnote 64 Along similar lines, Hassan Nasrallah, the Secretary-General of Hezbollah, claimed it natural for Iranians to have been worried about the consequences of the Syrian conflict as ‘war could have stretched to Tabriz, Tehran and Mashhad’.Footnote 65

Public perceptions on Syria accordingly shifted away from the Arab Spring narrative with the emergence of ‘excommunicating’ or takfiri groups in the Syrian opposition, especially after the advance of ISIS deep into Iraqi territory. The empowerment of radical takfiri groups condemning Shi’a Muslims as infidels did much to undermine sympathy among Iranians for the Syrian opposition. Secular Iranians resented the emergence of conservative Islamists, while the more religious Iranians saw their fears that the uprising was a foreign plot against the Shi’a and Iran confirmed. Therefore, the radicalization and ‘takfirization’ of the Syrian opposition greatly undermined the Arab Spring narrative among the Iranian populace.

4 The Evolution of Iranian Strategy after the Arab Spring

While the two framings of the Syrian situation were highly contested in Tehran during the first six months of the uprising, it was the geopolitical framing that eventually gained traction with the elite. A clear shift in that direction, in reaction to regional and international developments, can be traced to the end of summer 2011. On 18 August, President Barack Obama declared for the first time that ‘the time has come for President Assad to step aside’.Footnote 66 The Iranians interpreted this statement as marking a new phase in the Syrian crisis in which the United States and its allies were embarking on an interventionist policy of seeking regime change in Damascus.Footnote 67 While the Iranians were always opposed to an interventionist American role in the region and suspected the United States wanted to re-shape the Middle East through regime change policies directed at adversarial states, they now inferred that the United States had turned its gaze on Syria and was preparing to make a concerted effort to bring down Assad, thereby seriously undermining Iran’s forward deterrence posture. This Iranian perception was strengthened by the Saudi withdrawal of its ambassador to Syria, at the same time as Obama’s declaration, followed immediately by similar withdrawals on the part of Kuwait and Bahrain (Qatar had done the same a month earlier). It was precisely at this time that Rafsanjani made an important claim regarding these new developments: ‘Now the United States and the West in general and a number of Arab countries have basically declared war on Syria and ears are waiting by the moment for the rumble of missiles and bombs.’Footnote 68

Given that most of these Arab countries took a reactionary approach to the Arab Spring, particularly to the protests in Bahrain and Yemen, their support for the Syrian protesters was interpreted in Tehran as a geopolitical move—not one that could be framed according to the Arab Spring narrative. In particular, the Saudi shift on Syria was considered to mirror the new US policy stance of applying increasing pressure on Damascus, with a senior Saudi official claiming that ‘the King knows that other than the collapse of the Islamic Republic itself, nothing would weaken Iran more than losing Syria’.Footnote 69 In addition, Turkish Foreign Minister Ahmet Davutoğlu issued the country’s ‘final word’ to Assad on 15 August 2011, and on 28 August President Abdullah Gul declared that Turkey had ‘lost confidence’ in the Assad regime.Footnote 70 Turkish dialogue with Syria ended at this time.Footnote 71 The Syrian opposition was also largely anti-Iranian and explicitly declared its intention to change the political alignment of Syria and, consequently, the geopolitical map of the Middle East. The opposition protests included anti-Iranian chants and slogans, such as ‘no Hezbollah, no Iran’ and the burning of Iranian and Hezbollah flags.Footnote 72 Saudi Arabia, in particular, as one of Iran’s main rivals in the region, was among the main sponsors of many Salafi militant groups, with extensive reports of its founding and organizing groups such as Jaysh al-Islam.Footnote 73

Riyadh’s objective was to overthrow Assad and thus deliver a major setback for Iran. Moreover, Burhan Ghalioun, the leader of the Syrian National Council, Syria’s main opposition group at the time, declared that ‘the current relationship between Syria and Iran is abnormal . . . There will be no special relationship with Iran [i.e. after the toppling of Assad]’.Footnote 74 He also stressed that the change in relations would have an impact not only on Iran but on its allies as well: ‘As our relations with Iran change, so too will our relationship with Hezbollah. Hezbollah after the fall of the Syrian regime will not be the same.’Footnote 75 Iranians saw these developments, taken together, as a serious sign that significant geopolitical factors were now formally in play, shaping the course of the Syrian conflict. The war was no longer about the Syrian people, domestic reforms or human rights, but solely about geopolitical interests. In a meeting with Turkish President Recep Tayyip Erdogan in March 2012, Khamenei stressed Iran’s strong opposition to any US plans in Syria, stating that ‘the Islamic Republic of Iran will defend Syria because of its support for the Line [i.e. Axis] of Resistance in the face of the Zionist regime and strongly disagrees with any intervention of outside forces in the internal affairs of Syria’.Footnote 76

Initially, Iran’s support for Syria was limited to political and economic assistance along with international support through institutions such as the UN.Footnote 77 At the same time, however, it distanced itself from the Assad regime rhetorically and criticized the use of force against protesters, to appease the Iranian public. These mixed reactions indicated that the Iranian establishment’s initial assessment of the Syrian conflict was largely optimistic: protests had broken out relatively late, and the Syrian regime’s anti-Israeli position and independence from US influence were thought to endow Assad with greater legitimacy than some other rulers. Anticipating that modest reforms would secure the Syrian regime, Iranian support was relatively unobtrusive and decidedly non-military. As faith in Assad’s political survival weakened over time, however, Iran decided that the only way out was through coalition-building. The important point here is that Iran’s overarching forward deterrence strategy was threatened in Syria. In response to these threats, it resorted to a series of practical military strategies which were aimed at preserving that deterrence, each of which can be studied as a separate phenomenon in its own right. We accordingly divide Iran’s Syria strategy into four phases: (1) a ‘Basij’ strategy of establishing local militias in Syria; (2) a regionalization strategy of incorporating transnational fighters and militias in the war effort; (3) an internationalization strategy aimed at drawing in Russia and balancing the United States; and (4) a post-ISIS deterrence strategy to balance against the United States, Turkey and Israel. Through these four phases Iran’s Syria strategy has progressively escalated in response to the possible defeat of its ally and the deterioration of its forward deterrence posture through Syria and Hezbollah against Israel. Today, the potential for direct interstate conflict is increasing as proxy warfare declines and Iran attempts to maintain the credibility of its forward deterrence capacity.

4.1 Phase 1: Iran’s Basij Strategy

As noted above, President Obama’s declaration of August 2011 and Iran’s regional rivals’ increased backing of rebel forces initiated a shift in Tehran’s strategy towards Syria. As an international anti-Assad coalition emerged, Iran’s belief that the Syrians could themselves control the situation with minimal support was significantly weakened. It therefore became clear to Tehran that Iran needed to reformulate and upgrade its strategy to block its rivals’ advances in Syria. At this time, Iran’s principal move was to advise the Syrian government to create local militias, with the twin aims of safeguarding significant religious and political sites on the one hand and training the Syrian military and security forces for an asymmetric war scenario on the other. Both efforts were spearheaded by the IRGC. In his personal memoir, published after his death in Syria, General Hamidani described Iran’s initial involvement as advisory and as a response to the Syrian request for assistance with the immediate objectives of defending religious shrines and fighting opposition forces.Footnote 78 Training started in late 2011, only months after the perceived start of a wider regional campaign against the Syrian regime. It was not until the summer of 2012 that General Mohammad Ali Jafaari, head of the IRGC, admitted a Quds Force presence in Syria.Footnote 79

The Basij model, which comprises a bottom-up mobilization of volunteer fighters into paramilitary formations, developed out of Iran’s experience in the post-revolutionary period and in the Iran–Iraq War.Footnote 80 Iran’s own Basij model was replicated in Syria as the ‘People’s Popular Committees’ (al-Lijan al-Sha’biyah), which by the end of 2012 had merged into the new ‘National Defence Forces’ (Quwat al-Difa al-Watani). Iran has consistently sought to export the Basij model to other countries, including Lebanon, Iraq and Yemen. The war created the opportunity for Iran to pursue the same strategy in Syria. Cultural Basij centres were established in 14 Syrian provinces, with Hamidani claiming that ‘those centres were active even in provinces under the occupation of al-Nusra’.Footnote 81

According to the IRGC Deputy Head of the Basij, Mohammad Hussein Sepehr, ‘the greatest service that General Hamidani did for the Resistance Front was the creation of the popular Basij [in Syria] . . . composed of our Alawite and Sunni brothers’.Footnote 82 Moreover, Jafaari claimed that ‘if it were not for the emergence of the popular Basij in Syria, this country would have been divided into several parts and today we would not have the country of Syria’.Footnote 83 Likewise, in an interview with the Iranian Al-Alam TV, Assad confirmed that ‘in addition to advisers, there are groups of Iranian volunteers who came to Syria to fight and they are commanded by advisers and as a result Iran fought in Syria . . . however, not even one official Iranian military force is in Syria’.Footnote 84

In contrast to analyses exaggerating the costs of Iran’s involvement in Syria,Footnote 85 we argue that this military mobilization strategy served as a very cheap and effective way to enhance Syria’s security.Footnote 86 Moreover, by strengthening local allied militias, Iran prepared for the possibility of territorial fragmentation in Syria. Iran’s support for militias was thus a rational and limited contingency plan to provide for the event of Assad’s downfall. It would have given Iran coercive capacity to shape the post-Assad distribution of territory and spheres of influence, especially with regard to littoral Alawite heartlands and regions populated by religious minorities. In short, Iran’s Basij strategy aimed to shore up support for its struggling ally and to cut its own losses.

4.2 Phase 2: Iran’s Regionalization Strategy

While the militias were critical in providing the manpower and organizational capacity to enable the Syrian regime to undertake its military operations,Footnote 87 it was still not a sufficient strategy on its own to preserve Assad’s power, since the recruits were localized in Syria alone. The Syrian government still experienced reversals on the battlefield and was vulnerable to decisive setbacks, forcing Iran to reconsider its precise strategy. Tehran thus decided to pursue a regionalization strategy, expanding the scope and breadth of the Basij approach through regional coalition-building with both traditional allies such as Hezbollah and newly formed transnational militias willing to fight in Syria. This would not only bolster allied militias’ experience, ideology and strength but would also add support to the local militias already operating on the ground.

Hezbollah entered the Syrian conflict from Lebanon in several stages, beginning in 2013. In a speech regarding Hezbollah’s initial intervention in Syria, Nasrallah argued that Hezbollah was reacting to geopolitical developments and that it was ‘the last party to intervene’. He alluded to the importance of protecting ‘a front [the Axis of Resistance] that the world wants to destroy . . . targeted by an American, Israeli, takfiri project’.Footnote 88

Hezbollah moved into the border regions of Syria and Lebanon to prevent the infiltration and shelling of Lebanese territory by the armed opposition positioned around the Syrian city of Al Qusayr and to protect Lebanese villages in that region.Footnote 89 Perhaps even more importantly, the fall of Al Qusayr and its peripheral region would have enabled al-Nusra to cut Damascus off from resupply routes via Latakia. Tehran needed Hezbollah’s assistance in retaking the city as the Syrian Arab Army and its Iranian allies were not able to do so alone. The battle of Al Qusayr marked a turning point, as it was the first major military victory by the Syrian regime and its allies. Beyond the border regions, Hezbollah also positioned itself at the Holy Shrine of Lady Zaynab and established a foothold in Damascus.Footnote 90

It also advanced deep within Syrian territory to fight opposition combatants—securing Syrian territories bordering Lebanon from Al Qusayr across the border in northern Lebanon to Zabadani in the south.Footnote 91 In addition to Hezbollah, Iran organized transnational forces to take part in the conflict, recruiting and training fighters from Pakistan, Afghanistan and elsewhere in the Arab world—many of whom were motivated by religious and ideological loyalties to volunteer for the defence of the holy shrines. These recruits came to be known as the Fatimiyoon and Zaynabiyoon Brigades—parallel to developments happening within Iraq and the formation of the Hashd al-Shaabi (the Popular Basij). Iran has praised and promoted these fighters and defenders of the shrines (modafe’een haram), and has encouraged the production of music videos and documentaries about them.Footnote 92

Since much of the discourse and many of the symbols used in this process were explicitly Shi’a, Iran’s strategy could be perceived as sectarian. However, the Iranian propagation and framing of the conflict, which is itself another avenue. There is no clear information on the precise date and timings of this intervention. According to Hezbollah, however, the Al Qusayr battle marked the beginning.

For research, this should be seen in a more sophisticated light. Iranian narratives and policies have been simultaneously Shi’a-driven and cross-confessional, as Iranians have actively worked to integrate religious minorities, such as Christians and Druze, and even Sunnis, into the militias.Footnote 93 The results of these attempts can be seen in the Druze militias of Saraya al-Tawheed and Ammar bin Yasir Battalion, the Christian militias of Nusur az-Zawba’a and Sootoro, and the Sunni militia of Liwa al-Quds, in addition to the majority Sunni Syrian Arab Army. Iran clearly propagated the message of a threat to the Shi’a community and the need for the Shi’a to mobilize in self-defence, including the defence of holy spaces such as the shrines, while also portraying itself as the protector of religious minorities endangered by radical Wahhabi jihadists. This behaviour represents ‘sectarian identity without sectarian ideology’,Footnote 94 with an emphasis on a strong Shi’a identity, but not a sectarian ideology calling for the exclusion or genocide of those belonging to other sects (as espoused by many radical Wahhabi armed groups). This explains in part why Iran and its allies have been able to acquire the support of Christians and religious minorities in the war effort.

The regionalization of the Iranian coalition alongside allies like Hezbollah allowed Iran to ensure its forward deterrence capacity in the event of Assad’s fall, and to carve out a sphere of influence in Syria. Eventually, however, Iran chose to go even further to mitigate its vulnerabilities and guard against the potential failure of the regionalization strategy, by internationalizing its coalition in close cooperation with Russia.

4.3 Phase 3: Iran’s Internationalization Strategy

Though the regionalization of the Basij strategy proved effective in keeping Assad in power in parts of Syria, Iran still felt uncertain about the final outcome and therefore looked for other ways of ensuring victory for the regime.Footnote 95 On the one hand, ISIS had advanced deep into Syrian and Iraqi territory, approaching Iranian borders. On the other hand, the Syrian Arab Army had suffered a string of military defeats from March to June 2015.Footnote 96 As a result of these developments, the Syrian regime lost the entire province of Idlib in the north and Busra al-Sham in the south to the opposition and parts of Hama and Homs provinces to ISIS.Footnote 97 The loss of Idlib, in particular, meant that al-Nusra and its allies were positioned to overwhelm Latakia, a move which Iran and its allies, including Hezbollah, did not believe they could stop. Worried about the negative developments on the ground, Iran reached out to the Russians, who had just as much to fear as the Iranians in the loss of Latakia and the victory of the al-Nusra Front in Damascus, marking the beginning of a new, internationalizing phase in Iranian strategy.

This internationalization strategy was based on three main factors. First, Assad was failing to win the war, and the rise of ISIS contributed to the perception of an existential threat to his regime. ISIS declared its caliphate in June 2014, stretching from the suburbs of Aleppo and Syria’s borders with Lebanon in the west to Jalula and Sa’dia close to the Iranian and Iraqi borders in the east. Meanwhile, Syrian opposition forces were advancing in many areas all around the country, further demonstrating the serious threat posed to the Assad regime. It was obvious for Iran that a change of strategy was needed to overcome the Syrian impasse.

Second, Iran believed it needed to balance advances in US and Turkish positions within Syria that had been made in part as a consequence of the war against ISIS. Russian backing would allow Syrian troops and their allies on the ground to push back against opposition forces, including the US-backed Syrian Democratic Forces (SDF). The US had gained entry into the Syrian conflict and the fight against ISIS through its Kurdish allies. With a heavy footprint in Iraq, the United States decided to fight ISIS by supporting the Kurdish forces on the ground in Syria, where it lacked a commensurate presence of its own. Iran also wanted to balance the air power of the United States, which was providing air cover to its allies.

While its regional and local allies could assist with military operations on the ground, Iran lacked strong outside forces to balance the United States in the air. The third factor concerned domestic Iranian politics following the signing of the Iranian nuclear deal (Joint Comprehensive Plan of Action, JCPOA) in 2015, when Iranian conservatives sought to balance the successful outreach to the West under the administration of the moderate President Rouhani by engaging more closely with Russia against the United States and EU. Their goal was to prevent Iran from moving too close to a western orbit.Footnote 98

Achieving Russian participation in the war was considered the key to all three issues. Initially, Iranian–Russian cooperation took place through intelligence-sharing and political cooperation. In the shadow of the western intervention in Libya, Russia was wary of US plans for regime change in Syria, and played a key role in the UN National Security Council to shelter Syria, including after Syria’s alleged use of chemical weapons in 2013. More substantive Russian involvement was inaugurated with its military intervention in September 2015. Sulaymani was rumoured to have travelled personally to Moscow several times to discuss the feasibility and planning of the operation beforehand.Footnote 99 The resulting Russian intervention changed all the calculations in the Syrian conflict and solidified Assad’s position.

4.4 Phase 4: Post-ISIS Balancing

Iran announced the defeat of ISIS with General Sulaymani’s congratulatory letter to the Supreme Leader on 21 November 2017, marking a new stage in its Syria strategy.Footnote 100 In this letter, Sulaymani also expressed gratitude for the decisive role played by Hezbollah, the Hashd al-Shaabi and local and transnational fighters in the victory. Ayatollah Khamenei, in his official letter responding to Sulaymani, stated that the victory represented not just the defeat of ISIS but also ‘a heavier blow to the malicious policies [of conspiring actors] that . . . aimed to destroy the anti-Israeli Resistance and weaken independent states’.Footnote 101 He continued: ‘I emphasize that we should not be oblivious to the conspiracies of the enemy. Those who plotted this evil conspiracy with such heavy investment will not sit by idly; they will try to conspire in another region or in another form.’

Iran suspects the ‘plotting’ powers to be colluding with ISIS in order to fragment Syria. Foreign Minister Mohammad Javad Zarif has claimed that the United States seeks to divide SyriaFootnote 102—an unacceptable outcome for Iran that would undermine its forward deterrence posture. While ISIS has lost the vast majority of its territorial holdings, its re-emergence cannot be ruled out: a spokesman for the US Department of Defense warned of an ISIS ‘resurgence’ in April 2018.Footnote 103 The terror group has apparently smuggled US$400 million out of its territories to spread across legitimate revenue-generating businesses in the Middle East including extensive money-laundering enterprises in Iraq itself.Footnote 104 More importantly, a Pentagon study published in the summer of 2018 reported that between 20,000 and 30,000 ISIS fighters remain across Iraq and Syria and continue to carry out shock hit-and-run terror campaigns.Footnote 105

Like Obama, US President Donald Trump has been somewhat ambiguous on the American role in Syria, vacillating between military strikes on the country and statements of a desire to withdraw US forces from it. In actuality, Trump’s Syria policy is driven by two important objectives: the belief in a larger regional pushback campaign against Iran, and the desire to preserve some American presence on the ground in Syria so that the United States can be part of a post-war deal and exert leverage in negotiations with Iran, the Syrian government and Russia.

While the war against ISIS focused the attention of most regional and international actors on a unified target, attention is now more fragmented, with increased peripheral rivalry and friction between the key stakeholders in Syria coming to the fore. Three main stakeholders have emerged in the Syrian conflict: first, the Kurds and the United States; second, Turkey, stretching from the western banks of the Euphrates to southern Idlib and its own borders in Hatay province; and third, the Syrian regime’s own forces and allies, including Russia and Iran.

Given the territory and positions its rivals have managed to carve out within Syria, Iran is intent on balancing them and helping Assad to reconquer the entire country. The Iranians have always insisted that Syria should be maintained as a united state, seeing a Kurdish secession as threatening a regional domino effect endangering Iran’s own territorial integrity. Since this sensitivity is also shared by Turkey, one of the cornerstones of the Astana peace process initiated in winter 2016 is a recognition of Syrian sovereignty and territorial integrity.Footnote 106 Similarly, Iraq opposes territorial fragmentation, especially given the threat it faces from its own autonomous Kurdish region.Footnote 107 Indeed, since 2003 Iraq has constituted a key link in Iran’s Syria strategy, serving as a logistical base for Iran’s support to Syria and also providing fighters to bolster Assad: Iraqi militias reported to be active in the Syrian theatre include Asa’ib Ahl al-Haq and Kata’ib Sayyid al-Shuhada, among others.Footnote 108 An exclusive Reuters report in 2012 described how Iran was alleged to be sending military supplies to Syria on a massive scale via Iraqi airspace, with Secretary of State John Kerry threatening to ‘review US aid to Baghdad if it does not halt such overflights’.Footnote 109 Iraq was also host to a new intelligence-sharing centre established in Baghdad in 2015 with Iran, Russia, Syria and Hezbollah to coordinate the war effort.

Although the Syrian regime and its allies are gaining momentum on the ground, there is no guarantee that the Syrian government will regain full control of its territory, especially given the continued Turkish and US military presence in the country. Facing such a complex environment, the Iran–Syria axis is concentrating its military campaign on the territories outside the control of Damascus, with Iran having declared its plans to prioritize Idlib and Deir Ezzor in the upcoming phases of the war.Footnote 110

Deir Ezzor has been a critical site of confrontation between the US-backed SDF and the Syrian Army and its allies. The region holds considerable strategic value as a critical land corridor abutting Iraq and the last stronghold of ISIS. As ISIS power ebbs in the region, both of the two opposing forces are anxious to monopolize control over the area, as evident in the clashes reported in Spring 2018.Footnote 111 Idlib, on the other hand, is the last stronghold of al-Nusra forces and other armed opposition fighters. The Turkish and Iran–Syria camps may face each other down in this key battleground, just as they threatened to do in Afrin in early 2018.

Beyond these two theatres, Iran will also focus on supporting the Syrian forces fighting to reconquer opposition enclaves deep inside Syria, including the south, as witnessed in the fierce battles in eastern Ghouta in Spring 2018. The Syrian Army and its allies, including Iran, have been preoccupied with preparations for these battles.

Besides these two theatres, the question of Israel is more important than ever in the post-ISIS period. Like the other main stakeholders in Syria, Iran is also pursuing deterrence towards Israel to secure its hard-fought gains. Given Iran’s preoccupations in the conflict and its imperative of managing rival actors within Syria with limited resources, Tehran does not consider the pursuit of direct conflict with Israel a strategic priority.Footnote 112 That said, it is certainly seeking to safeguard its forward deterrence vis-à-vis Israel, which Sulaymani described in January 2018 as an aggressive actor ‘with 300 nuclear warheads’ and a doctrine of ‘pre-emptive strikes’.Footnote 113

The first half of 2018 had seen significant tensions between Israel and Iran within Syria. Immediately after the rocket barrage on Israeli positions in the Golan in early May, Israel again attacked Syria, claiming to have hit all Iranian installations throughout the country. While Iran has largely remained silent on these developments, in a major speech following this episode Hassan Nasrallah declared that ‘the missile attack in the Golan established a new phase and the enemy [Israel] must make new calculations on Syria’.Footnote 114 Syria and its allies have re-established deterrent capacities against Israel, and the cost of Israeli attacks in Syria has been raised.

This represents a clear shift in Nasrallah’s position on the rules of engagement with Israel. At the beginning of 2018 he had stated: ‘The circumstances impact the rules of engagement. For example, in Syria there may be a strike against one of our targets, and sometimes some of our targets are hit, but we do not retaliate [immediately].’Footnote 115 By May, however, this ambiguous stance had been abandoned, with references to ‘a new phase’ requiring ‘new calculations’ by Israel.Footnote 116 Not long after that, Shamkhani said in an interview that ‘Israel should not attack our forces in Syria’ and that ‘Syria and its allies will not allow the blood of its martyrs to be wasted, and Israel understands this very well’.Footnote 117 These actions on the part of Syria and its allies should be evaluated in terms of deterrence. In the same speech in May 2018, Nasrallah referred explicitly to the role of the Resistance in establishing deterrence on the Golan Heights, stating that ‘what happened in the occupied Golan is one form of response to the Zionist attacks on Syria and those in Syria, whether it be the people, the Syrian Army, or its allies’.Footnote 118 Hezbollah and Iran, in other words, would retaliate if attacked.

He emphasized that the establishment of the Resistance on the Golan was both ‘a right’ and ‘a choice’, and added that ‘an international source told Israel that if it expanded the response, the other missile strike would be in the heart of occupied Palestine’.Footnote 119 The Supreme Leader has also stated repeatedly that the time of ‘hit and run’ is over.Footnote 120 If Iran hesitates, it will suffer a high cost in terms of its reputation. The consequent risk of an escalatory cycle highlights the need for caution on all sides in Syria.

5 Conclusion

Iran’s Syria strategy has evolved over the course of the seven long years of war. We have argued in this chapter that the logic driving Iran’s relationship with Syria has been that of acquiring and securing ‘forward deterrence’. Progressively escalating in response to Tehran’s sense of new threats and vulnerabilities, Iranian strategy in Syria has advanced through four stages, from a phase of localized militia formation through the regionalization and then internationalization of its coalition to the current balancing strategy of the post-ISIS period.

Iran does not consider the post-ISIS period in Syria to be the final stage of the conflict. The Assad government and its allies still need to reconquer the entirety of Syrian territory, a challenging goal given the presence of the United States and Turkey within the country. As proxy warfare has largely wound down, the possibility of direct interstate conflict has increased. This is evidenced by the fact that the major arenas of conflict are now confined to Idlib and Deir Ezzor, with Turkey exercising direct control over its proxies, effectively disarming the heavy weapons of the Turkish-backed ‘National Liberation Front’ and establishing joint Turkish–Russian patrols in the demilitarized buffer zones.Footnote 121

At this point, Iranian goals are shaped by the rivalry between regional and international powers as it seeks to balance them and to consolidate its hard-won position. As part of this balancing, Iran considers it essential to have deterrent capacity to protect its positions within Syria from military threats, not just from the United States and Turkey’s allies but also from Israel. If Israel can attack and undermine Iran within Syria, Iran’s balancing capacity vis-à-vis the United States and Turkey would be harmed, in terms of both reputation and operational effectiveness. That, in turn, would undermine the likelihood of victory—Iran’s principal objective in the Syrian war.

The future form of Iran’s Syria policy will depend to a great extent on the continuing evolution of the conflict, and the deterrent value of the militias in Syria, including their role in Iran’s forward deterrence posture. It is highly unlikely that the militias will be disbanded, and the question of Iran’s influence and relationship with the militias after the conflict will continue to be a critically important issue. Bearing in mind the forward deterrent logic of Iran’s strategy via allies, as explicated in this chapter, the continued existence of the militias will be of much higher importance for Iran than a formal Iranian presence in Syria. Iran will thus support the Syrian regime in its increasing efforts to reassert its power and sovereignty and to fully indigenize the Syrian militias once the conflict subsides.

Over the years ahead, Iran’s Syria policy will also be increasingly shaped by the United States’ Iran strategy. Now that President Trump has pulled the United States out of the JCPOA and decided to exert maximum pressure on Iran, the Iranian threat perception of potential escalation has increased. Consequently, Tehran feels an urgent need to demonstrate its deterrence capacity, and the value and role of Syria as part of its forward deterrence will only increase. Iran–Syria relations will therefore continue to operate at a strategic level in the years to come.