Mehmet Emin CengizThe Future of the Iranian-Turkish Relationship: A Contained Geopolitical Rivalry or A Possible Escalation Between Ankara and Tehran?
Abstract: The Turkish-Iranian geopolitical rivalry has been growing increasingly tense as of late. Although the two countries have different political directions, priorities and conflicting interests, over the past decade, the two contained their rivalry and managed to have a working relationship thanks to the regional climate in the Middle East after Donald Trump’s electoral victory in the US, coupled with the significant trade volume between the two that is primarily based on Turkey’s purchase of expensive Iranian natural gas and crude oil for many years.
Nevertheless, recently the trade volume between the two has been in decline, the areas that brought Turkey and Iran together since 2016 have been evaporating, and more importantly, since US President Joe Biden took office, Turkey has been mending ties with Iran’s regional rivals ranging from Saudi Arabia to Israel. All these factors amplify the likelihood of a more overt rivalry between Tehran and Turkey that can manifest in different theatres from Syria and Iraq to the South Caucasus in the upcoming period.
Introduction 
The long-standing geopolitical rivalry between Iran and Turkey is entering a phase of tension. Over the past decades, compartmentalization[i] of different issues has been the primary driver of the relationship between Tehran and Ankara. However, the tension between the two countries emanating from various theatres is likely to increase in the upcoming period as the number of areas of collaboration between the two declines. Ever since the start of the turbulent Arab Spring period, the Ankara-Tehran rivalry was best crystallized in the Syrian theatre following the outbreak of protests in the country in 2011.
Iran, at the outset of the Arab Spring, positively approached the phenomenon of protest waves in countries such as Egypt and Tunisia, capitalizing on the idea that it would lead to a positive relationship with the new rulers of these countries, namely political Islamists. Iranian officials also saw the street protests and uprisings as a blow that would end the dominance of ‘‘secular political schools’’ as well as the ‘‘Zionists and Americans.’’[ii]
That being said, when the protest waves of the Arab Spring reached Syria, Iranian officials’ stance turned upside down. Iran, since the beginning, viewed the Syrian crisis as an existential threat, contemplating that Tehran’s security starts from Damascus. To this end, Iran became an essential part of the Syrian conflict through its proxies and Islamic Revolutionary Guard Corps (IRGC), and steadily supported the Syrian regime forces. Despite Iranian efforts, the Syrian military opposition groups took control of large swathes of Syria in the early years of the war.
When the Assad regime was on the verge of collapse, Qasem Soleimani, the commander of Iran’s elite Quds force, the external wing of the IRGC, flew to Moscow and allegedly convinced Russian President Vladimir Putin to join the war on Assad’s side.[iii] The course of the war changed dramatically as Russia directly joined the war in September 2015. The Syrian opposition started losing ground in a short period as the ruthless Russian air support coupled with the ground support of Iranian-backed militias helped the Assad regime regain control of many areas it had previously lost to the opposition.
Turkey, on the other hand, saw the Arab Spring as a chance to increase its regional clout in the countries that faced turbulence. Syria was one of these theatres. In parallel to this objective, Turkey has been supporting the opposition groups fighting the Syrian regime. Nevertheless, in order to de-escalate tensions in the country in 2017, Russia, Turkey, and Iran launched the Astana process. This took a parallel process to the one already going on in Geneva and formed a watershed moment in the course of the war.
Meanwhile, the Astana process was an opportunity for the regime and Russia to restructure the war in their favor. The Bashar al-Assad regime benefitted from the process, as it and its allies later captured[iv] three of the four de-escalation zones specified in the Astana process under the pretext of fighting against terrorists/terrorism. Nonetheless, despite all odds, Turkey curbed its disagreements with Iran in the Syrian conflict to a large extent.
Evaporation of the Factors That Have Brought Ankara and Tehran Together 
Donald Trump’s victory in the presidential elections in the US in 2016, and his backing of the counter-revolution axis of the Arab Spring consisting of Egypt, UAE, and Saudi Arabia alongside Israel, coupled with the significant trade volume between Turkey and Iran, further brought Ankara and Tehran closer. Both countries seemed quite suspicious of a new regional order that was coming into existence with US backing at the time.[v]
In this setting, both parties acted suspiciously towards the US. Specifically, anti-US sentiments have intensified in the aftermath of the attempted coup in July 2016 in Turkey, where it is widely believed that the US was one of the parties behind the coup attempt.[vi] Meanwhile, the UAE was also accused of funding the sinister coup attempt.[vii]
In this atmosphere, Turkey and Iran had common threat perceptions, and they viewed that they were being excluded from the emerging regional order that was premised on a closer collaboration between the anti-Arab Spring camp and Israel and backed by the US.[viii] This regional picture led to closer cooperation between Iran and Turkey.
This period also led to the Eurasianist wing in Turkey having greater influence on Turkish foreign policy decisions. These decisions were reflected in multiple bids ranging from Turkey’s procurement of the Russian-made S-400[ix] long-range air defense missile systems-which resulted in the US removing Turkey from the very prestigious F-35 program,[x] and imposing Countering America’s Adversaries Through Sanctions Act (CAATSA) sanctions[xi]– to Turkey’s assertive foreign policy in the Eastern Mediterranean through the Blue Homeland vision as well as closer cooperation with China.
Turkey’s assertive foreign policy also led to the country’s exclusion from the EastMed Gas Forum.[xii] Turkey’s orientation to Eurasia ignited heated debates about Turkey’s position within NATO in Western circles up until the outbreak of the Russian invasion of Ukraine, which put an end to questions on Turkey’s role within NATO. On the contrary, Turkey has become a principal player in NATO’s expansion, as observed in Finland and Sweden’s bid to join the alliance.
In addition to the abovementioned points, the Qatar blockade contributed to closer cooperation between Iran and Turkey.[xiii] Both countries were concerned they would receive a blow to their regional significance if Qatar conceded to the demands of the anti-Arab Spring bloc. In this regard, both supported Doha in the face of the pressure exerted on it by Riyadh, Cairo, and Abu Dhabi.[xiv]
Moreover, the Kurdistan Region of Iraq’s independence referendum in 2017[xv] similarly strengthened bi-lateral ties. Iran’s population of Kurds is second only to Turkey, which has the largest population of Kurds in the Middle East.[xvi] Thus, both parties fiercely opposed the independence referendum, which they viewed as an existential threat. While the KRI has long maintained strong relations with the US and Israel in particular, Israel was in fact the only country that openly supported the referendum at the time,[xvii] something which only contributed to Tehran’s fears.
As a result, the KRI’s independence referendum was suffocated. The Kurdistan Region of Iraq furthermore faced significant setbacks as it lost control of most of the disputed territories[xviii] in clashes with the Iraqi forces supported by the pro-Iranian Al Hashd Al Shaabi militias.
Moreover, trade volume between Turkey and Iran has been very important in containing their rivalry over the past decades. Since 2018, both sides have reiterated their desire to increase their trade volume to 30 billion dollars.[xix] On the sidelines of President Erdoğan’s last trip to Tehran on July 19, 2022, which took place within the framework of the Astana process, this intention was voiced once again.[xx]
Nevertheless, the trade volume between the two countries has been decreasing and the pandemic and US sanctions reimposed on Iran a year after Trump’s arrival do not seem to be the pivotal causes.[xxi] In 2017, the trade volume between Tehran and Ankara was over 10 billion dollars,[xxii] yet this number decreased over the years. Lately, the trade volume has been around 7.5 billion dollars.[xxiii]
While Turkey is the biggest buyer of Iranian natural gas, Iran is the second biggest exporter of gas to Turkey after Russia.[xxiv] Needless to say, Tehran does not want to lose this standing. However, Ankara seems to have a different calculus which will be disclosed in the parts below. All the aforementioned points led both sides to maintain a working relationship for quite a while. Despite diverging views on many issues, Tehran and Ankara compartmentalized their relationship and curbed their rivalry.
Nevertheless, the geopolitical picture in the region has lately changed quite dramatically, and the areas that brought Tehran and Ankara together are evaporating.
Current Areas Which Drive a Wedge Between Tehran and Ankara 
The bones of contention between Tehran and Ankara are on the rise. What is more, the geographical scope of their geopolitical rivalry has enlarged. In addition to Syria, today, Iraq and the South Caucasus have also been added to the areas of rivalry between the sides. The Second Nagorno Karabakh war that transpired in 2020 changed the dynamics in the area in Turkey’s favor, increasing Tehran’s fears.
While Turkey tremendously aided Azerbaijan through its advanced drone technology so that the country could reclaim its territories, Iran tacitly sided with Armenia due to a number of reasons.[xxv] Foiling Turkey’s increasing role in the region was one of the reasons. Yet, Azerbaijan emerged triumphant in the war, and Turkey extended its footprint in this area.
According to an expert on Iranian affairs who is based in France and talked to the author on condition of anonymity, the Second Nagorno Karabakh war has intensely aggravated Iran’s fear of Turkish expansion, which is highly lambasted in the Iranian media.[xxvi] Although even before the Karabakh war Iran was at odds with Turkey in other areas, such as in Iraq and Syria, the rhetoric of Iranian officials and media was not intensely hostile as they viewed themselves as victorious in these two arenas in their rivalry with Turkey.
Nonetheless, in the Karabakh war, Turkey seems to be victorious, leading to a massive reaction from the Iranian side.[xxvii] The likelihood of opening the Zangezur corridor in South Armenia, which has come to the fore against the backdrop of Turkey’s political normalization with Armenia, has further increased Iran’s discontentment. If the Zangezur corridor is opened, Turkey can reach the Turkic states of Central Asia through Azerbaijan and Russia. Namely, if this project materializes, Iran will receive a blow to its geopolitical position.
Therefore, the Iranian side has constantly shown dissatisfaction with regard to the opening of the corridor. The latest example of Iranian discontent was evident in the statement of Ayatollah Ali Khamenei, the supreme leader of Iran, on the sidelines of his meeting with President Erdoğan in Tehran that Iran would oppose any attempt to block the Armenia-Iran border.[xxviii]
In the meantime, Turkey ‘‘seeks to improve its overall strength and global standing by transforming its soil into a central hub for energy transfer pipelines extending westwards toward Europe in order to achieve the strategic goal of creating a balance that moderates Iranian and Russian control over the supply of energy to Europe.’’[xxix]
For this purpose, Turkey attaches importance to Azerbaijani natural gas. Azerbaijan has already delivered its first shipment of gas to Europe through the Southern Gas Corridor, which connects the Caspian Sea to Europe.[xxx] Even so, if realized, the Zangezur corridor, not in the short term but the long run, may serve Turkey’s purpose of becoming a transit energy hub.
This is not to mention Iran’s own eagerness to become a natural gas provider to Europe, especially if the country reaches an agreement with the West regarding the revival of the Joint Comprehensive Plan of Action (JCPOA), and the sanctions imposed on Tehran are lifted. Thereby, Turkey’s close cooperation with Azerbaijan directly conflicts with Iranian interests. The natural gas file is of fundamental significance for both sides as it can shape the trajectory of the Turkey-Iran relationship in the upcoming period.