Iran’s Military Strategy

Hadi Ajili and Mahsa Rouhi

On 20 June 2019, Iran’s Islamic Revolutionary Guard Corps (IRGC) shot down a United States RQ-4A Global Hawk BAMS-D surveillance drone over the Strait of Hormuz using its new Seveom-e-Khordad air-defence system. The incident was the culmination of rising tensions in the Persian Gulf and nearly caused an armed confrontation between the two countries. US President Donald Trump called off a retaliatory attack at the last minute. The episode reflects Iran’s confidence that, despite obvious asymmetries, its regional power and reach enable it to deter the US military from acting against Iran. Since the US and others perceive Iran as a major threat to regional security and stability, it is important to analyse its military strategy and understand its drivers, objectives and implications.

Some Western officials and analysts argue that Iran’s military strategy is offensive in nature, aimed at expanding Iran’s power and ultimately restoring the Persian Empire; others see it as primarily defensive. Neither characterisation is accurate. Iran’s military strategy, while it includes forward-defence elements, is primarily focused on deterrence. Recognising the severe limitations of its conventional military capabilities due to sanctions since the 1979 revolution as well as depletion as a result of the Iran–Iraq War, Iran has resorted to unconventional approaches, including partnerships with non-state actors, to establish its military deterrent. Unable to confront threats or challenges directly, Iran has instead focused on points of weakness in its main adversaries in order to render their cost–benefit calculations unfavourable to attacking Iran. As Iranians see it, the deaths of American troops have considerably more serious domestic political ramifications for a US president than Iranian military fatalities would have for the Iranian leadership. This consideration has shaped Iran’s multilayered strategy for deterring military actions against it, especially an American attack, by increasing the cost of war for adversaries.


Five key drivers shape Iran’s military strategy. The first is historical distrust and ongoing confrontation between Iran and the US, which has kept regime change and military conflict on the table. The second driver is military self-reliance: Iran has to provide for its own security without foreign support. The third, due to decades of sanctions, is the need to optimise military expenditures and develop indigenous military technologies. Fourthly, given the mismatch it faces between threats and resources, Iran has been compelled to adopt an asymmetric-warfare strategy. Finally, Iran’s geopolitical position in a region that hosts competing and sometimes conflicting interests, and that has given rise to a strong US presence, has been critical in determining Iran’s regional military strategy.

The distrust between Iran and the US dates back to 1953, when the American and British governments engineered a coup against Iran’s prime minister, Mohammad Mossadegh, for geopolitical reasons. Since then, each side has compiled a long list of grievances. Iran’s includes the United States’ support of the brutal, pro-Western regime of Mohammad Reza Pahlavi – the shah of Iran – and American backing for Iraqi president Saddam Hussein in the Iran–Iraq War. Extreme strategic and ideological tension between Iran and the US has since endured. Iranian leaders have accused the US of supporting various activities to topple the regime, and strongly believe that US policy on Iran aims ultimately for regime change, which Washington could choose to achieve by military invasion. As a result, Iran’s military strategy has developed primarily to ensure a robust response against a US invasion or regime destabilisation so as to deter military action.

The Iran–Iraq War, which lasted from 1980 to 1988, has had a major influence on Iranian military strategy. Iran’s missile programme was primarily a consequence of that war. After the Iraqi invasion in 1980, Iran sought to purchase from the Soviet Union an inventory of Scud-B missiles to respond to Iraqi attacks. But the Soviets had an alliance with Iraq at the time, and refused to provide the missiles. International sanctions barred Iran from procuring missiles elsewhere. Meanwhile, the Soviet Union, the US and the Gulf Cooperation Council (GCC) nations provided Saddam Hussein with sophisticated military equipment and critical intelligence. During the war, Iran first acquired Scud-B missiles from Libya and Syria, then from North Korea. Immediately after the war, deprived of any other sources, Iran turned to North Korea for 200–300 of them. Iran also purchased surface-to-air missiles, fighter aircraft and armoured vehicles, but its military spending was and has remained small compared with many Gulf Arab states with far less territory. Iranian military expenditures shrank by about 30% between 2006 and 2015 as a result of sanctions.1 Even when sanctions were partially lifted in 2015 and 2016, military spending returned only to 2009 levels – about 3% of GDP, far lower than the 12% reached in the 1970s under the shah.2 The GCC states had an expected combined military expenditure of $100 billion in 2019, versus about $17.4bn for Iran.3

The Iran–Iraq War also reflected a historical conflict between Iran and its Arab neighbours. Even prior to the 1979 revolution, Iraq was perceived as Iran’s top security threat. During the war, the GCC countries provided Saddam with logistical and financial assistance – by the CIA’s estimate, $30–40bn.4 While the 2003 US intervention in Iraq relieved tension between Iran and Iraq, Iraq’s friction with the GCC countries, especially Saudi Arabia, has only intensified. Thus, Iran sees two main security threats: a territorial invasion involving US forces, and a proxy war in the broader region that threatens Iran’s interests and security. Iran’s military strategy is designed to deter both these eventualities.


Given the existing balance of power and US interests in the region, the US would probably lead any invasion of Iran or become involved soon after it started. Thus, Iranian assessments of US military strategy, operations and tactics are crucial to its own military strategy. Iranian military analysts have gleaned that US planners consider it imperative to suppress enemy air defences prior to undertaking land operations; to disrupt the enemy’s command, control, communication and computers (C4) through electronic warfare; and to maintain superiority in intelligence, surveillance and reconnaissance (ISR) systems and armoured forces. The US emphasises air operations in the early phases of a conflict, including the bombardment of the enemy’s infrastructure and establishment of air superiority. Additionally, the US leverages power projection by way of forward-deployed assets, including military bases in the Middle East, carrier strike groups and other warships. The US also places a premium on psychological warfare and, of course, comprehensive technical superiority.

To counter these strengths, Iran has designed an asymmetric strategy whose conceptual underpinning, also broadly adopted by countries such as North Korea, China and Russia, is anti-access and area denial. Anti-access capabilities are meant to prevent an opposing force from entering national territory or operational areas, while area-denial capabilities focus on limiting capabilities of the opposing force within such areas. The former include diverse ballistic and cruise missiles; long-range ISR systems such as satellites, drones and radar; submarine forces; cyber-attack capabilities for disrupting command-and-control systems; and special-operations forces able to engage in conventional and unconventional warfare. Area-denial capabilities include air forces and air-defence systems that blunt an adversary’s air capabilities; anti-ship missiles and torpedoes to target naval forces; precision rockets, artillery and missiles for targeting surface vessels; electronic warfare for degrading an adversary’s command-and-control centres; land and naval mines; armed speedboats for use in coastal waters and straits; special-operations forces to engage within a designated area; and uninhabited aircraft or underwater vehicles for use in intelligence collection or kinetic operations.5

Thus, Iran’s deterrence strategy rests on five key operational pillars: fixed and mobile air defence; artillery and ballistic missiles; electronic and cyber warfare; limited use of airpower; and naval combat.

Fixed and mobile air defense

Air-defence systems are an especially important component of Iran’s military strategy in light of the United States’ operational prioritisation of air superiority. One of the most vital elements of Iran’s air-defence system is the integrated network that coordinates surveillance and radar systems utilised by all regular military branches and even the Basij militia. Western forces’ increasing use of air-to-surface anti-radiation missiles to suppress enemy air defences has impelled Iran to make its system more mobile and compact with recent upgrades, such as Sevom-e-Khordad. This is a domestically produced advanced air-defence system that utilises mid-range, high-altitude, solid-fuel Sayyad-2 missiles. It is capable of engaging four targets simultaneously in the range of 50–75 kilometres at an altitude of 25–30 km. Its compactness and mobility afford it considerable agility, suitable for asymmetric tactics. The Sevom-e-Khordad system facilitated Iran’s shoot-down of the US drone in June, more broadly illustrating its utility in area-denial operations.

Ballistic missiles

Buffeted by sanctions, the Iranian military now relies heavily on its ballistic- and cruise-missile programmes. Moreover, as Michael Elleman and Mark Fitzpatrick have pointed out, ‘the need for missiles is also embedded in the national psyche, from the days in the mid-1980s when acquiring and firing back Scud missiles was the only way to retaliate against Iraqi missile strikes on Iranian cities’.6 Iran now has the largest such missile programmes in the region.7 This has allowed the country to improve its anti-access capabilities with the ability to target military bases and aircraft carriers in the region. The missile programme also enables Iran to demonstrate its military power through test launches and military exercises, strengthening its deterrent. Iran relies on mobile launchers and tunnels to increase missile survivability, and its launching pads are scattered throughout the country. These factors complicate enemy pre-emption or prevention.

Iran’s missile programme is, of course, highly controversial and one of Iran’s main bones of contention with the West and regional adversaries. Iran possesses a wide variety of missiles, and there are different estimates of their exact ranges. Iran’s longer-range missiles are mainly the Qadr-F, Sejjil and Khorramshahr. Iran has argued that permissible range should be determined according to strategic threats, such as that posed by Israel, and emphasises that any negotiations on Iran’s missile programmes should be in the context of a regional arms-control agreement.

Nevertheless, concern about Iran’s missile programme centres not only on intended targets, but also more broadly on the composition of what Elleman and Fitzpatrick call the ‘largest and most diverse arsenal in the Middle East’, and the standing threat to stability it poses.8 In a 2017 US assessment of ballistic- and cruise-missile threats, the US Defense Intelligence Ballistic Missile Analysis Committee indicated that Iran would seek an intercontinental ballistic missile (ICBM) in order to challenge the US, and warned that the development of Iran’s space programme ‘could shorten the pathway to an ICBM because space-launch vehicles … use inherently similar technologies’.9

While the development of space launchers over the past ten years has advanced the Iranian missile programme, it still faces significant limitations. The maximum range of Iranian missile systems is approximately 2,000 km, well short of intermediate and intercontinental ranges. As detailed by a 2018 IISS assessment, Iran’s Shahab-1 and Shahab-2 short-range missiles were originally obtained during the Iran–Iraq War in the 1980s, mainly to resist and ultimately deter Iraq. Other missiles include the Shahab-3, Sajjil-2, Qiam, Ghadr and Emad, and some are capable of carrying a nuclear payload.10

In withdrawing from the Joint Comprehensive Plan of Action (JCPOA) – the Iran nuclear deal – the Trump administration cited the lack of restrictions on Iran’s ongoing ballistic-missile programme as evidence that the deal was ‘disastrously flawed’, arguing that president Barack Obama ‘turned a blind eye’ as Iran expanded the missile programme.11 The missiles could be the delivery vehicles for any nuclear weapons. For some 35 years, however, the main purpose of Iran’s ballistic missiles has been anti-access and area denial, and that is likely to remain the case for the foreseeable future. More recently, Iran has focused on improving the accuracy of its short-range missiles, such as the Fateh-110, rather than increasing their range. With substantially greater precision, they are now more effective anti-access/area-denial weapons. Thus, Iran credibly regards its ballistic missiles as tools not only for deterrence by punishment but also, and to a greater extent, for deterrence by denial.

Electronic and cyber warfare

Over the past decade, Iran has developed an array of domestic electronic-warfare capabilities, including battlefield tactical communications equipment resistant to electronic-warfare measures, various command-and-control mechanisms, military-satellite jammers and various ciphering systems. Iran has recently expanded its capabilities, stressing electronic support measures, electronic countermeasures, electronic counter-countermeasures, and disruption of GPS and satellite communication, with some radar systems reportedly having ranges of up to 500 km.12 A prominent example of Iran’s electronic capabilities involved its hijacking of the advanced, stealthy US RQ-170 Sentinel drone in December 2011, which purportedly required the Iranians to override the drone’s guidance system. Iran has also developed signal-intelligence-gathering technologies that are useful in conducting electronic warfare. Hizbullah used some of these capabilities during its 2006 war with Israel to neutralise Israeli electronic-warfare capabilities, evidenced by the Israeli systems’ failure to block Hizbullah’s command and communications, Hizbullah’s ability to eavesdrop on Israel’s communication from inside Lebanon, Hizbullah’s electronic interference with Israel’s Barak anti-missile missiles aboard Israeli warships, and Israel’s inability to jam communications out of the Iranian Embassy in Beirut.

Given that cyber attacks rarely become public and are generally deniable, it is difficult to pinpoint Iran’s cyber capabilities, but they are improving. They are a crucial part of the country’s military strategy, in particular its strategic-depth doctrine. In line with its broader strategy of deterring and countering adversaries, it has a two-pronged outlook, focusing firstly on the US and secondly on regional adversaries such as Saudi Arabia and Israel. The successful Stuxnet virus attack on Iran’s Natanz uranium-enrichment plant in 2010 was a turning point for Iran’s cyber strategy. Iran realised that cyber should become a major pillar of its military strategy, rapidly improved its defensive and offensive cyber capabilities, and developed a fuller appreciation for cyber’s effectiveness as a tool of asymmetric warfare. Iran has since conducted cyber operations against the Saudi oil industry and Western (including US) financial services.13

Iran’s main cyber priority, however, is defensive: to identify the vital points of vulnerability in its own infrastructure. A report by the British technology firm Small Media indicates that in 2015 Tehran had increased its spending on cyber security by 1,200% over a two-year period.14 Iran has devised different measures to protect its C4 assets through the formation of the Provincial Corps and organisational changes in the IRGC that confer on each corps commander the authority to take action outside the chain of command in the event of communication failures. The Iranian military has purchased, developed and implemented encoding technology to secure critical military and national-security communications. Iran’s cyber strategy and its investments in cyber capability since 2010 broadly fit within its deterrent posture insofar as they work towards an ability to impose significant costs on potential enemies in a military confrontation.

Limited use of airpower

In the face of superior US, Israeli and other regional air forces, Iranian countermeasures include layered and mobile large-scale air-defence systems, man-portable air-defence systems and automatic anti-aircraft artillery, with tactical roles assigned to fixed-wing aircraft and helicopters. Iran’s air assets also include various reconnaissance, surveillance and combat drones, which have been used in the Syrian war owing to their ability to perform night-time as well as daytime missions in most weather conditions, to reach a wide range of stationary and mobile targets, to fly by remote control and on autopilot, and to hide and evade.

Naval combat

Iran’s regional naval doctrine rests mainly on ultra-fast speedboats and anti-ship cruise missiles. It is rooted in the Iran–Iraq War, in which Iranian forces executed frequent attacks on enemy forces in the Gulf using speedboats at low cost and with disproportionately positive results. Although various weapons systems would ultimately destroy these craft in a sustained engagement, the Iranian rationale is that only one boat need get through enemy defences to cause significant financial damage in a kamikaze-style attack. According to some reports, Iran has between 3,000 and 5,000 speedboats that can be used to execute ‘swarm attacks’ on larger ships, such as aircraft carriers. Iran has been perfecting such attacks, in which up to 100 armed speedboats approach an enemy warship from all directions. Surprise, confusion and speed are essential to their effectiveness, and the confined space of the Strait of Hormuz, which is only about 32 km across at its narrowest point, increases the probability of a successful swarm attack.

Iran has also emphasised the importance of anti-ship cruise missiles to deterrence in the Persian Gulf, developing short-range ones that can be launched from a variety of naval platforms (including speedboats) to target enemy warships. Sea mines too figure in Iran’s naval strategy, especially in the Strait of Hormuz, as cost-effective tools. In particular, Iran can employ real mines along with thousands of fake ones, making it very difficult for minesweepers to neutralise the threat and decreasing the pace at which enemy naval forces can mobilise.

Strategic depth and influence in the region

Iran’s Middle Eastern neighbours are increasingly alarmed by its activities, including not only its ballistic-missile programme but to an even greater extent its support for Hizbullah, the Bashar al-Assad regime in Syria, Shia militias in Iraq and the Houthis in Yemen, as well as its contentiousness vis-à-vis Israel. From an outside perspective, Iranian depredations in the region have arguably made outside intervention and regional conflict more rather than less likely, and thus weakened deterrence. Certainly they have intensified the regional security dilemma.15

From Iran’s perspective, however, relaxing its regional posture and conduct would not ensure that its adversaries would stop trying to weaken or change its regime, while maintaining its stance has strengthened its deterrent. For example, the attack on Saudi Arabian oil facilities at Abqaiq dramatically reduced Saudi crude-oil production to half the normal level in a matter of hours. While Tehran has denied any involvement and the Houthis have claimed responsibility, the larger point is that Iran is recognised as being capable of executing such an operation and willing to do so, whether directly or through the Houthis. Thus, the episode demonstrates that Iran can inflict significant strategic costs on its adversaries should a war break out. Given that the Houthis could have executed the attack with Tehran’s support, the role of non-state proxies in Iran’s broader deterrent strategy appears vindicated. In turn, proxies’ proven utility effectively expands Iran’s strategic depth to Syria, Lebanon, Iraq and Yemen, which enables Iran to limit risks to its own territory. And Tehran can use non-state proxies to signal capability while plausibly denying culpability.16

Iran has a long history of using non-state actors to deter regional threats that predates the 1979 revolution. The shah supported a Kurdish insurgency against the al-Bakr government in Iraq to deter Iraq from acting on long-standing claims over parts of the border river between the two countries. During the war with Iraq, Iran gradually reorganised banished Iraqi militias, which formed the basis for the Badr Organisation. Even after that war ended with the two sides’ acceptance of a ceasefire pursuant to a UN Security Council resolution, Tehran feared that Saddam would attack again, so it continued to support Iraqi insurgent groups. The United States’ 2003 invasion of Iraq had a strong impact on Iran’s strategy. Initially, Tehran feared a US attack, as the Bush administration intimated that Iran itself could be next. Accordingly, Tehran intensified efforts to build partnerships and networks among Iraqi insurgent groups for use both as deterrent assets and as leverage in potential negotiations. During the Obama administration, though negotiations on the nuclear deal eased bilateral relations, US forces in the region continued to pose a credible threat of a US military strike on Iran. In response, as part of its so-called mosaic defence, Tehran employed its partnerships and networks to signal that Iran could inflict damage on US assets in the event of American airstrikes on Iranian nuclear facilities or air bases.

Iran’s support of the Houthis in Yemen is a celebrated example of regional military-proxy activities considered provocative. It is widely reported that Iran has sent advanced conventional weapons, including missiles, as well as military advisers to support the rebels against the recognised government, which is militarily and financially supported by Saudi Arabia, the United Arab Emirates and, indirectly, the United States.17 Whatever its particulars, Iran’s support for the Houthis is simply intended to bleed its principal regional rival, Saudi Arabia, so as to drain it of resources to mount a direct war with Iran. Indeed, Iran’s spending behaviour suggests that its regional ambitions and objectives are calibrated. Between 2011 and 2015 – when multilateral sanctions were in force and Iran faced reduced oil exports – Iran decreased its military expenditures while actually expanding its role and presence in Syria, Iraq and Yemen.18 Some reports indicate that Iran spends about $140 million per month in Syria and provides less than 1% of the ground forces needed to protect the Syrian regime, compared to the $6bn per month Saudi Arabia spends in Yemen.19

In the last decade, Iran has effectively outsourced direct war-fighting responsibility to Hizbullah, Iraqi Shia militias, and Shia mercenaries from Afghanistan and Pakistan. Iran’s way of war in Syria suggests that the IRGC is perfecting a minimalist form of unconventional warfare whereby it deploys small expeditionary units that link up with and command militias in the battlefield. ‘If the IRGC has, indeed, mastered this ability, then it has positioned itself to use small numbers of conventional forces on foreign battlefields to produce effects disproportionate to their size’, says a report sponsored by the American Enterprise Institute.20 The prospect of being drawn into a protracted ground conflict appears to have discouraged regional and world powers from directly intervening in Syria.

Applying the strategy

While great powers have long possessed and employed anti-access/area-denial capabilities, they are now more widely available to middle powers, weaker states and, in some cases, even non-state actors. They enable inferior enemies to confront the United States at multiple operational and strategic levels. Iran lacks the benefit of an allied great power. While it has expended considerable effort to develop the capabilities to produce a nuclear weapon, it has elected not to do so. Accordingly, Iran has felt compelled to find other ways to deter a superpower. By developing and reinforcing its surface-to-surface ballistic-missile, anti-ship ballistic-missile and cruise-missile capabilities, Iran has improved its ability to target military bases, ships and aircraft in the region and thus to execute anti-access missions. It has also developed integrated and layered area-denial capabilities. And it is making these strides in an extremely cost-effective way, given the asymmetry in power and resources between Iran, on one hand, and the United States, Israel and the Gulf Arab states on the other.

To be sure, there have been multiple instances of destabilising ‘close encounters’ or provocations.21 During the first seven to eight months of 2017, there were at least 14 ‘unsafe and/or unprofessional interactions’ between US and Iranian maritime forces, after 35 in 2016 and 23 in 2015.22 In March 2017, Iranian speedboats came within 600 yards (550 metres) of a US ship, and in August 2017, an Iranian drone followed the USS Nimitz aircraft carrier and approached US FA-18 Hornet fighter aircraft, with some other encounters occurring in the Strait of Hormuz.23 US officials have reiterated the dangers of such encounters numerous times, calling Iran out for aggressive conduct that could lead to dangerous and rapid escalation. Such incidents largely stopped in mid-2017, but provocations have resumed since the United States’ disavowal of the JCPOA and ratcheting up of sanctions.

Despite such close encounters and explicit threats by militarily superior states, Iran has challenged the US and its allies’ interests in the Middle East for decades and, in Tehran’s view, has so far deterred an attack by the US or Israel. Washington and its regional partners might contend that Tehran’s strategy is not really a deterrent strategy at all due to its extra-territorial and provocative qualities. But Iran’s proactive behaviour is an unavoidable manifestation of the unconventional methods it has been compelled to adopt to compensate for its military shortcomings in the face of security threats posed primarily by the United States and Israel. Iran is not seeking to become a major military power. Its main objective is rather to establish an effective deterrent at low cost. While it may seek to project its regional influence, it is doing so on the cheap, which is inconsistent with grand strategic designs.

Posted on International Institute for Strategic Studies Nov 2019-Jan 2020

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