Turkey and Iran have been rivals since long before there was a Turkey or an Iran. Since the emergence of the Safavid Empire in the early 16th century, and spanning 300 years thereafter, Persia and Turkey – then the Ottoman Empire – fought wars for control of the Caucasus, the Fertile Crescent, and the hearts and minds of Muslims throughout the world. Empires and dynasties rose and fell but the rivalry lived on, dying down only in the 19th century, as both sides became too weak to resist the growing menace of the Europeans. By the Cold War, Turkey was a NATO member and an important component in the containment line around the Soviet Union.
It wasn’t until the late 20th century and the fall of the USSR that Turkey was free to define its own security needs. Lately, Turkey and Iran have been cooperating closely in Syria, they have boosted bilateral trade, and they’ve even worked together to protect Qatar from the Gulf state blockade. But those security needs put Turkey and Iran at odds with one another. Renewed antagonism is inevitable.
In an earlier Deep Dive, we analyzed the fighting readiness of the Turkish military in the aftermath of the 2016 coup attempt. We considered how its command structure and relation with the central government had changed as a result of the failed coup. This Deep Dive will carry that discussion forward and ask: How do Turkey’s military capabilities stack up against its greatest Middle Eastern rival, Iran? It will show why, given each country’s military abilities and the reality imposed on them by geography, their rivalry is most likely to manifest as proxy battles over buffer zones, not as outright state-to-state wars similar to those that have dominated most of their ancient histories. These zones of competition will be in Iraq and Syria, with the potential for the occasional – and very volatile – confrontation in the South Caucasus.
In the wake of the Cold War, the Turks looked out at an increasingly chaotic Middle East and realized that securing the homeland would require more than a large, defensive conscript army. Ahmet Davutoglu, Turkey’s prime minister from 2014 to 2016, outlined his country’s strategic needs in his 2001 book “Strategic Depth.” He argued that Turkey would need to secure an ever-larger buffer space to keep threats as far from central Anatolia and the Bosporus as possible. Until recently, Turkey had more or less placed this strategy on the back-burner and focused on modernizing its military and fighting Kurdish militants within its own borders.
In the past two years, however, Turkey’s quest for greater depth has begun in earnest. In August 2016, it invaded Syria in an effort to eliminate the Kurdish militias along Turkey’s southern border. With those Kurds pushed deeper into Syria, Turkey’s own Kurdish fighters in the country’s southeast would have nowhere to go to flee the government’s crackdown. To achieve true strategic depth, however, Turkey needs to push even farther south, into the lands of the Ottoman Empire and up to the Zagros Mountains. Historically, when an eastern power is able to amass significant force west of the Zagros, in modern-day Iraq and Syria, it is bad news for whoever occupies Anatolia. (We should note that this doesn’t mean Turkey needs to expand its literal borders. It need only be the region’s dominant power, to have de facto control of what happens there.)
The problem is that Iran needs the same territory for the same defensive reasons. When the Soviet Union fell, Middle Eastern states that had been dominated by the Soviets began to turn once again to Sunni Islam as an organizing concept. This was a threat to Iran, a majority Shiite country that already had to contend with a hostile Iraq – also a majority Shiite country but one with a much larger Sunni minority than Iran – under Saddam Hussein in a war that spanned from 1980-88. This would not be the last time Iran faced a major threat on its border with Iraq: the U.S. occupation in 2003 triggered Iranian intervention, as did the rise of the Islamic State in 2014. The lesson for Iran was that when it doesn’t control Iraq (and, for added security, Syria), it is too easy for major threats to emerge.
A renewed rivalry between Turkey and Iran is unavoidable. But it won’t resemble the rivalry of old.
Mountains, Real and Figurative
The most obvious obstacle to conventional war between Turkey and Iran is NATO’s principle of collective defense. Turkey was part of the first enlargement of NATO back in 1952. Though the alliance is facing something of an existential crisis, and its collective defense component has been enacted only once in its 69-year history, NATO is still an imposing shadow hovering over any would-be aggressor. That said, even if President Donald Trump were to dismantle NATO today, there are other barriers in the way of direct warfare between Iran and Turkey.
The first thing to note is that an Iran-Turkey war would be extremely costly for both sides because, when the full breadth of their fighting capabilities is taken into account, they are evenly matched. Including its gendarmerie, Turkey has approximately 512,000 active-service soldiers; Iran has 523,000 when the Revolutionary Guard is counted. They have similarly sized populations from which to draw recruits – both about 80 million people. Iran spends slightly more on its defense – $16 billion in 2017 compared to $12.3 billion for Turkey.
When it comes to hardware, Turkey has a decisive advantage. For starters, Turkey has more battle tanks, armored personnel carriers and artillery than Iran, and most of its equipment is of better quality (though Iran does have more multiple rocket launchers). Iran’s military is largely equipped with materiel acquired before the Islamic revolution in 1979, much of which at this point is of dubious functionality. In a pitched battle on open, flat terrain, this would tip the balance in Turkey’s favor unless Iran could control the skies.
Poor serviceability certainly describes Iran’s air force, which is not only smaller than Turkey’s but also composed of planes that are several decades old. (The exception is a low number of domestically produced aircraft, such as the Saegheh, which are themselves derivative designs of older aircraft.) According to the International Institute for Strategic Studies, only about 60 percent of Iran’s U.S. models and 80 percent of its Russian models of aircraft are usable. Though Turkey also has some old jets, its inventory of approximately 260 F-16Cs and F-16Ds sets it apart. The F-16’s range exceeds that of any fighter ground attack plane in Iran’s arsenal, and its weapons systems are newer. Additionally, and critically, Turkish Aerospace Industries has a license from General Dynamics to produce F-16s domestically, which means Turkey would be able to replenish its air force without foreign support – albeit slowly – whereas Iran would not.
Iran would not be completely helpless against Turkey’s air force. The Iranians have an array of Soviet- and French-designed anti-air defense systems. Their long-range systems, the S-200 Angara and S-300PMU2, have effective targeting ranges of 120-200 miles (190-320 kilometers) and maximum altitudes of 130,000 and 88,500 feet, respectively. These would not completely deny Turkey entrance to Iranian airspace, but they would force Turkey to accept a higher casualty rate.
That said, from Turkey’s eastern air base in Diyarbakir, its air force could reach key Iranian cities such as Tabriz, Isfahan and Tehran. The mere ability to threaten major cities from the sky would give Turkey an advantage in cease-fire negotiations. The same cannot be said for Iran. Even from its westernmost air bases, striking Ankara or Istanbul would be at the edge of or beyond the range of its fighter ground attack fleet (except maybe for its handful of F-14s). And of course, Turkey has its own air defenses, although somewhat surprisingly Turkey’s inventory is older than Iran’s. (This explains why Ankara has been so eager to acquire new Russian S-400s.)
But although Turkey has the edge in conventional terms, not all that makes Iran’s defensive capabilities formidable is conventional. Both militaries are structured for different purposes. Turkey’s large army was designed to deter invasion, which is why it employs universal conscription. Its short conscription period of 12 months, however, precludes its non-professional cadre from developing the experience that would make it a highly effective fighting force in large-scale offensive operations. Instead, Turkey would have to rely on its much smaller special operations forces, which were particularly hard hit in the purges that followed the 2016 coup attempt.
Iran also has a conscript military, with a 21-month conscription liability. But in addition to its 350,000-strong army, it has the elite Islamic Revolutionary Guard Corps. In theory, Iran’s army protects the country’s territory and the IRGC protects the Islamic revolutionary regime. But in practice, the IRGC has been largely responsible for Iran’s foreign interventions in the Middle East via its expeditionary arm, the Quds Force, which inevitably also contributes to the integrity of the Iranian state. Further, Iran has spent decades establishing pro-Iran militias in Iraq, Syria, Lebanon and Yemen, many of which are formally incorporated into the Quds Force chain of command. Iran, in other words, has a fighting force with significant and recent offensive fighting experience, whereas Turkey has, up until its 2016 and 2018 interventions in Syria, been primarily focused on deterring invasion and rooting out domestic terrorists and rebels. (Turkey has also conducted constant but low-tempo operations in northern Iraq for years to keep pressure on Kurdish groups that it considers a threat.)
Iran’s familiarity with urban warfare via its militant proxy groups means that even if Turkey were to move against Iran, the Iranians would have ample capability to station forces behind the front to disrupt Turkey’s supply lines. Moreover, the ability of these militias to wage persistent and decentralized insurgency means they would make holding land costly for Turkey. After all, it was difficult for even the United States to maintain control of Iraq after rapidly invading and subduing it in 2003.
To be sure, Turkey is gaining experience working with militias in Syria. But it is new experience, and the goal of Turkey’s proxies is ultimately to control territory of some sort or another in Syria. Iran’s militias, on the other hand, often act explicitly with Iran’s regional interests in mind. They are also already spread out and entrenched across Syria and Iraq, where they could cause the maximum trouble for a Turkish invasion force.
So although Turkey is the clear winner in terms of military hardware – both technologically and numerically – Iran has deeper experience waging offensive campaigns and a pre-established proxy network with which to do so. Direct conflict between the two states would cost a great deal of money and blood.
Even if they were willing to pay the price to fight a conventional war, they’d have to overcome geography. Capture of each other’s capitals is out of the question. Tehran is deep inside Iran’s borders, shielded by the Zagros Mountains. This was no accident. At the peak of Ottoman-Safavid competition, Iran’s capital was in Tabriz, which is located much closer to the southern outlets of the Caucasus passes in northern Iran. After Ottoman forces had repeatedly sacked Tabriz, the Safavids relocated their capital southeast to Isfahan. (It was later moved to Tehran under the Qajars.)
Off and on for more than a century, the Ottomans and the Safavids attacked one another. They would take a little land, only to lose it when winter came and broke their supply lines. Eventually, in 1639, they signed the Treaty of Zuhab, which set borders between their empires that are nearly identical to the modern borders of Turkey, Iraq and Iran – an acceptance of the limitations set by geography.
On the flip side, Ankara is quite far from Iran, about 630 miles, and is protected by the mountainous Anatolia. Istanbul, Turkey’s most important strategic city, is even farther – about 800 miles. There are some important eastern cities that are closer – Erzurum, Diyarbakir and Kars (the terminus of the Baku-Tbilisi-Kars railway) – that could be threatened by an Iranian offensive through the Caucasus. But the most densely populated area of Turkey and its four most populous cities – Istanbul, Ankara, Izmir and Bursa – are located in the west.
Turkey could attempt to threaten Iran by going north through the Caucasus and trying to invade via Armenia or Azerbaijan. Though by no means easy to cross, the Armenian Highlands is one of the few ways to traverse the northernmost extent of the Zagros, making it a path through which Turkish and Iranian armies have passed throughout history to threaten one another’s territory. In fact, the South Caucasus is another area, like Iraq and Syria, where Iran and Turkey could compete for influence.
The problem here is that the South Caucasus is under constant observation by the Russians. Russia is determined not to let anyone gain a strong enough position in the South Caucasus that they could threaten the Russian heartland via the North Caucasus. The Russians battled Turks and Persians for control of the region throughout the 18th and 19th centuries. Indeed, the Soviet Union drew the borders of the South Caucasus specifically to keep the region as divided as possible. Should either Turkey or Iran try to control the South Caucasus to threaten the other, Russia would step in to back the defender.
These are the boundaries to Turkey and Iran’s rivalry. They are unlikely to fight one another directly because of alliances and the high costs of war against a relative peer. Moreover, invasion of the other’s territory is difficult because of the terrain and limited routes.
Astute map readers may have noticed, however, that there is another route that Turkish forces could take into Iran. The Zagros Mountains are a formidable wall on Iran’s western border, but they get smaller as they span south. The parts of the range east and southeast of Iran’s Khuzestan province contain several passages that are crossable. From there, it is possible to threaten Isfahan province.
Unsurprisingly, then, this is the route that major invasions have taken in Iran’s past. Alexander moved through the Persian gates onto Persepolis and Pasargadae (northwest of modern-day Shiraz), then to Ecbatana (near the modern-day city of Hamadan), which ultimately led to the fall of the Persian Achaemenid Empire in 330 B.C. Saddam Hussein in 1980 also attacked Khuzestan province, with the immediate goal of seizing the province’s oil fields. Had Saddam taken control of Khuzestan, not only would Iran be deprived of its Persian Gulf coast, but Iran’s core would also have been threatened. When the Rashiduns erupted out of the Arabian Peninsula in the seventh century, they too entered Persia through the southern portion of the Zagros. Khuzestan, therefore, acts as a critical western buffer zone to Iran, and Iran will be particularly aware of any uprisings fomented among its sizable Arab population (the region has a history of Arab separatism).
For Turkey to exploit this weak spot in the southern Zagros, however, it would need to secure control of the buffer space in Iraq between itself and Iran – and Iran already has a head start. Though Turkey is active in operations against the Kurdistan Workers’ Party militant group in northern Iraq, it is Iran that has the stronger presence in Iraq via its Popular Mobilization Forces, not to mention Iraq’s own security forces would resist a Turkish invasion of their country. Trying to conquer northern and central Iraq would demand military capabilities and economic resources beyond what Turkey can bring to bear at the moment.
But although Iran has this area well defended, it also is in no position to push its control of the buffer zone up to Turkey’s borders or beyond. Almost all Persian invasions into the Ottoman Empire were limited to incursions into what is now Syria and Iraq. This is in part due to the flat terrain in these countries, which makes them easier to traverse and thus capture – but also easier to lose. The southernmost extent of Turkey lines on a flat plain, but the southeastern Anti-Taurus Mountains, as well as the Tigris and Euphrates rivers, act as barriers to advance.
This is the space where Turkey and Iran’s rivalry will play out. It is likely to develop in the form of economic and proxy militia competition in Iraq and Syria and in the South Caucasus. Indeed, though their actions are not yet focused on one another, the contest is well underway. Iran has established friendly militias throughout the buffer, and only now is Turkey beginning to push into northern Syria and northern Iraq. The empires are gone, the militaries have changed, but the geography and the security needs of Turkey and Iran are the same.