Turkey’s policy on Syria since the start of the uprising in March 2011 has continually evolved due to the realization of the gap between its ambitions and capabilities, as well as changes on the ground due to the actions of other state and non-state actors.

Even before the Arab Spring, Ankara had ambitions to project power in the region. However, developments in Syria, which was a test case for the limits of Turkey’s power projection, led it to revising its approach more than once.

Ankara is a staunch critic of Syrian President Bashar al-Assad and supports the Syrian opposition, although Assad and his Turkish counterpart Recep Tayyep Erdogan were close before the uprising.

Ozgur Unluhisarcikli, head of the German Marshall Fund in Ankara, said Turkey’s policy toward the uprising quickly evolved from the doctrine of “zero problems with neighbors,” to trying to overthrow Assad by actively supporting the armed rebellion and calling for international intervention, either via a full invasion or a no-fly zone.

“After the failure of this approach, due to both its incapability and lack of support from others, Turkey’s current policy toward Syria can be defined as damage control,” Unluhisarcikli told Al Arabiya English.

Turkey hosts almost 3 million refugees, on whom it has spent about $10 billion so far. However, Ankara has started closing its borders in the past few months because its open-door policy has been abused by foreign jihadists wanting to join the Islamic State of Iraq and Syria (ISIS), and by the group’s militants to conduct suicide bombings in Turkey.

Ankara “is trying to cope with several challenges emanating from a destabilized Syria, the most pressing one being the refugee crisis, while the recent Russian military presence in Syria renders Turkey’s options limited,” Unluhisarcikli said.

He added that Ankara’s recently hardened position toward Syrian Kurds has cost it the peace process with its own Kurdish population, and Turkey today is challenged by both the Kurdistan Workers’ Party (PKK) and ISIS.

“Several hundred citizens, including security personnel and civilians, have been victim to ISIS and the PKK since last year. What started as a dream to project Turkish soft power to Syria has turned into a nightmare for Turkey,” he said.

As part of the U.S.-led coalition against ISIS, Turkey has allowed other members to use its southern Incirlik airbase for strikes in Syria.

It also launched its first airstrikes against ISIS in Syria in Aug. 2015 as part of the coalition.

Ankara and Washington implemented a $500-million program to train and equip Syrian rebels against ISIS in May 2015.

However, the first phase ended in failure last July after the abduction of fighters by Al-Qaeda’s Syrian affiliate the Nusra Front before they even started fighting.

Retired diplomat Unal Cevikoz, who served as Turkey’s ambassador to Iraq from 2004-2006, said although Ankara’s anti-Assad obsession received some sympathy and support from the international community at the outset, this has changed.

“Turkey’s Syria policy has been mainly built on three pillars: to replace Assad and his regime with favorable opposition forces; to prevent refugees entering Turkey and push for a safe zone in Syria; and to avoid advances by the Kurdish Democratic Union Party [PYD] in northern Syria,” Cevikoz told Al Arabiya English, adding that today none of these targets is achievable.

Squeezed by its domestic Kurdish problem, Ankara is increasingly critical of the PYD and its Peoples Protection Units (YPG) militia, an affiliate of the outlawed PKK.

Turkey recently started shelling the U.S.-backed YPG across the border to push it to abandon captured territory in northern Syria, fearing the potential creation of a Kurdish state there. However, this has created tensions with Washington.

Cevikoz said Russia’s increased involvement has turned the tide in Syria, and pushed Washington and other coalition members to consider coordinating with Assad against ISIS as the only way forward.

“Turkey will tacitly have to comply with this,” he said, adding that Ankara is unable to counter PYD advances in northern Syria.

“Due to a risk of Russian retaliation and further escalation with Moscow, Syrian airspace is closed to Turkish planes, and a ground offensive is equally impossible.”

Cevikoz said the refugee problem would probably worsen in the spring of 2016, and grow beyond Turkey’s control.

“As the EU’s demands from Turkey are politically costly, Ankara would be unwilling to integrate the refugees into Turkish society, but will probably take some limited steps to keep the EU engaged in order to obtain more concessions.”