Here’s what an uncoordinated US withdrawal from Syria would look like. It’s bad for many partners, but especially Turkey.

Reports have surfaced regarding the possibility of the United States withdrawing from Syria completely. Despite officials rejecting these reports and a recent vote in the US Senate exhibiting reluctance among lawmakers to leave Syria, news of a potential US exit has been closely monitored by regional actors. Turkey is among them. While Ankara may favor a future US withdrawal from Syria, it desires US coordination. An uncoordinated withdrawal by the United States could pose significant risks for Turkey, leaving the country alone against Iran and Russia.

Since 2014, when the Barack Obama administration searched for a local partner force in Syria to fight against the Islamic State of Iraq and al-Sham (ISIS) without opposing Iran, the relationship between Turkey and the United States has deteriorated. The US partnership with the People’s Defense Units (YPG), the Syrian branch of the Kurdistan Workers’ Party (PKK)—a designated foreign terrorist organization—was viewed by Ankara as a national security threat. However, in early October 2019, the situation got more complex when Turkish President Recep Tayyip Erdogan and former President Donald Trump agreed on a partial US withdrawal. Trump later ordered a full withdrawal, but it was prevented at the last minute by a decision to secure oil in Syria. Shortly after, in October 2019, the Turks launched Operation Peace Spring and entered parts of northern Syria. However, Russia secured the majority of the territory from which the Americans withdrew, following a deal between the YPG-dominated Syrian Democratic Forces (SDF) and Damascus. The Russians effectively protected the SDF against Turkish attempts to launch new cross-border military operations.

If a complete US withdrawal from Syria is going to occur, Turkish decision-makers would prefer the United States to coordinate with Ankara. This option would allow different scenarios and roadmaps to facilitate US and Turkish interests in Syria and the broader region. For Turkey, a US withdrawal is not significant; the crucial question for Turkey is how the United States will withdraw.

In the event of an abrupt US withdrawal similar to what happened in Afghanistan, the Turkish government may face difficult decisions and encounter new threats from Syria. One of the most notable threats would come from Iran.

Iran is the best positioned to fill the void

The US forces in Syria rely on a single point of entry from Iraq for their logistical supply line. As a result, they will have to withdraw from the south to the north and retreat into Iraq gradually. Due to insufficient infrastructure, an airlift is not a viable option. In this scenario, Iran’s network across the Syria-Iraq border region around Abu Kamal in Deir ez-Zour makes it well-positioned to fill the void left by the United States. This would allow Iran to expand its only land supply route from Tehran to Beirut. Iranian militias on the western side of the Euphrates River would likely cross to the eastern side and enter former US zones of influence.

At the same time, Russian presence in SDF-controlled areas would enable the Russian military to move further eastward and control the entire Turkey-Syria border up to Iraq. The YPG-dominated SDF would probably negotiate with Damascus and trade its control over parts of Syria for official recognition and legitimization by the state. A potential agreement may be founded on shared hostility toward Turkey and the Syrian opposition. As a result, Iran would gain control over the oil-rich regions of Syria and expand its influence across the Syria-Iraq border. Conversely, the YPG would gain official status in Syria and ally itself with Russia, Iran, and the Bashar al-Assad regime, which could be troubling for Turkey.

To address the threat posed by the YPG in Syria, Turkey would need to secure the Kurdish-populated areas along its border. This decision would involve a military operation, and could potentially escalate tensions with Russia and Iran. This risky move could help Turkey limit the threat posed by the YPG, but could also be a premature birth of a battle in Syria.

The Turkish Achilles heel: Hayat Tahrir al-Sham

Regardless of Turkey’s actions in northeastern Syria, it will face significant pressure in the northwest. The Syrian conflict would then transform from a three-axis conflict into a two-axis conflict. In this new scenario, Tehran, Moscow, Damascus, and the YPG would probably aim to expel Turkey from Syria and enforce a military resolution to the conflict by dispossessing the Syrian opposition from their territory. Turkey and the Syrian opposition would then need to confront a new alliance of these four actors, which could tip the balance of power against them.

It has been reported that negotiations between Ankara and Damascus were not resolved due to the Assad regime’s insistence on a complete withdrawal of Turkish forces. On the other hand, Ankara argues that a withdrawal would have negative consequences for the political process and could lead to a mass migration of up to four million Syrians into Turkey. This scenario would be detrimental to Syria and result in significant domestic repercussions for Turkey.

In 2020, Turkey risked a confrontation with Russia and Iran after witnessing a similar situation. After thirty-four Turkish soldiers lost their lives in a single night, Ankara conducted a drone campaign that caused great destruction to the Syrian regime forces and Iran-backed Shia militias. Despite being alone in Idlib governorate, Turkey managed to successfully defend Idlib. However, this new scenario would have no US military presence in the east. Iran would have expanded its influence and secured a more stable logistical line from Iraq into Syria. Emboldened by the US withdrawal, Iran would likely be more aggressive.

Turkey’s primary vulnerability is Hayat Tahrir al-Sham (HTS) in Idlib, where it faces mounting military pressure. The opposing alliance is likely to exploit the terrorist designation of HTS to launch a military operation in the name of counterterrorism. Such a step could lead to a new humanitarian disaster for more than three million people living in Idlib, as Iran and Russia are likely to exploit the HTS issue both militarily and diplomatically against Turkey.

The Russian invasion of Ukraine is likely to reduce the amount of Russian investment available for a military escalation in Idlib, leaving Iran and its proxies to drive the attacks against Idlib. The Russian limitation presents an opportunity for Turkey to leverage its new domestically produced drones and air-defense systems, which were not present in 2020, to counter Iran.

In that case, Iran may seek to enhance its ties with the YPG, which the United States previously supported. This could result in a wider escalation of tensions across Syria. Similar to the current Iranian attacks against US bases in Syria and Iraq, Iran would use the PKK and its Syrian branch, the YPG, to attack Turkish forces in Syria and Iraq.

Ankara may initially perceive a potential US withdrawal from Syria as a positive development; however, the outcome could vary significantly based on how the US withdraws. Turkey would prefer a well-coordinated and orderly withdrawal process in close collaboration with its NATO ally. If the United States decides to withdraw from Syria without any coordination, it may lead to the handover of the US partner forces and the US zone of influence to Iran. In such a scenario, Iran would likely prioritize removing Turkey from Syria, as Ankara would be the only obstacle to Syria becoming a puppet state of Iran.

Ömer Özkizilcik is a nonresident fellow for the Syria Project in the Atlantic Council’s Middle East Programs.

Image: Turkish troops return after a joint U.S.-Turkey patrol in northern Syria, as it is pictured from near the Turkish town of Akcakale, Turkey, September 8, 2019. REUTERS/Murad Sezer