Turkey and Syria are now at war – but the ultimate arbiter of what happens next is likely to be Vladimir Putin.

Eight long years of proxy war between Turkey and the Syrian regime have now morphed into direct confrontation between the two sides. In recent weeks, battle has raged for control of Idlib, with mounting casualties, a mass exodus of refugees, and manic manoeuvring by all the major powers in Syria. This is the final stretch of the Syria’s civil war.

Idlib is the last rebel-held enclave in north-western Syria and home to 2-3 million Syrians living in areas controlled by various Sunni opposition groups, including Turkey-backed opposition forces and Hayat Tahrir el-Sham (HTS), an al-Qaeda derivative. In December, the Syrian army, backed by Russian air strikes, started its long-awaited Idlib operation, advancing north and capturing key towns along the way. According to the United Nations, the fighting between the opposition forces and the Syrian army has already displaced more than half a million people, many making their way northwards towards the Turkish border.

Turkey already hosts 3.7 million Syrians, and another million Syrian refugees are living just outside its border, dependent on Turkish humanitarian aid coming across. Turkish officials know that a new wave of Syrians forcing Turkey to open its borders once more would be economically difficult and politically catastrophic, due to growing anti-refugee sentiment and criticism of Ankara’s Syria policy among the Turkish public.

Turkey already hosts 3.7 million Syrians, and another million Syrian refugees are living just outside its border

But Ankara’s options are few. Turkey wants to push back against the Syrian offensive and prevent an exodus from major population centres in the area – and, if possible, protect Turkish-backed Sunni militias until a final settlement in Syria is reached. Initially, Recep Tayyip Erdogan lobbied Vladimir Putin to slow the Syrian offensive. Then, Ankara stepped up its support for Sunni opposition forces in Idlib. And finally, this week Turkey entered the foray itself.

Over the past two weeks, the Turkish military has been mobilising in large numbers in northern Idlib and is now actively fighting the Syrian army, aiming to recapture key towns along the M4 and M5 highways that cut across the province, such as Saraqib. Thirteen Turkish soldiers have died in air and artillery attacks by the Syrian army in the last two weeks – and, despite superior capability and the presence of a large contingent of Syrian opposition forces, Turkey’s advance is hampered by the fact that Russia controls the air space over Idlib. Turkish and Russian delegations have met twice in Ankara but so far no resolution has been reached.

For Ankara, this is not just a nightmare in terms of a potential new influx of refugees, but it is also a tough test of its ties with Moscow. Frustrated with US cooperation with Syrian Kurds, in 2017 Turkey struck a deal with Russia and Iran, called the Astana process, to create a new order in Syria. Coming amid constant tensions with Washington and with a decision looming for Turkey to buy the S-400 missile system from Russia, the Astana process brought Vladimir Putin and Erdogan politically closer together and established a new modus vivendi in northern Syria. With Turkish-US ties weakening, Ankara felt that Moscow held the key for it to be able to operate in Syria. Russia asked Turkey to curb support for Syrian opposition forces in Idlib, most notably the HTS and other radical groups, and in return it gave a Turkey the green light for its incursion into Kurdish-dominated Afrin and subsequently further east of Euphrates.

But, along the way, Ankara and Moscow never saw eye to eye on Idlib – or on the legitimacy of the Assad regime. Erdogan has consistently spurned Russian proposals for Turkey to normalise relations with Syria. Ankara’s vision for Idlib was one of containment, both in terms of refugees and the Sunni groups there, whereas Moscow wanted to eliminate HTS and other groups it considers “terrorists”, and for the province to ultimately fall under Syrian jurisdiction. In 2018, the Astana partners agreed that Turkey would establish 12 military outposts to monitor a ceasefire between the regime and the rebels. Since then, the Syrian regime has incrementally increased its territorial hold, today encircling nearly half of the Turkish military outposts and pushing for the control of M4 highway.

Turkey’s options at this point seem limited because it does not control the air space over Syria and because the price of a direct confrontation with Russia is too big. In addition to purchasing S-400s, Turkey has undersigned two major infrastructure projects, including the Turkish Stream pipeline that connects Russian gas underneath the Black Sea to Turkey, bypassing Ukraine; and a consortium to build Turkey’s first nuclear reactor. Turkey is dependent on Russia for natural gas and tourism revenues and does not want to risk an all-out Russian offensive in Idlib that would drive refugees north. 

The Turkish president this week warned several times that the “Syrian regime would pay a heavy price” , and Turkey has been shelling Syrian army targets as it continues its mobilisation in the area. But what Erdogan has carefully avoided doing is publicly holding Russia accountable for Idlib. By focusing on the Syrian regime alone, he is probably hoping to use his hotline to Putin as the final crisis management tool. As often with Idlib, Putin and Erdogan will hold another phone call any one of these days and talk about how to de-escalate. 

A likely scenario is a new partitioning of the province along the M4 and M5 highways, with Turkey controlling the northern areas adjacent to its border. Currently, the Turkish army is targeting Syrian regime positions and backing Syrian opposition groups to recapture territory around the highways. And, over the past few days, the Syrian military, backed by the Russian air force and Iranian militias, has taken control of the M5 for the first time since 2012.

The war of attrition for this small piece of land will likely continue until Erdogan and Putin agree a new ceasefire plan. Turkey has been trying to enlist Europe and the United States on its side, but beyond supportive statements and future offers of stabilisation aid, there is little Western powers can do in Idlib. At least in this part of the world, the ball is now in Putin’s court.

Read more on: Wider Europe, Turkey, Russia, The Middle East and North Africa, Syria / Iraq / Lebanon

The European Council on Foreign Relations does not take collective positions. This commentary, like all publications of the European Council on Foreign Relations, represents only the views of its authors.