Turkey in Syria: Key Issues for U.S. Policy

Key Chapter Title List

1. Turkey's Relationship with HTS
2. HTS and Other Relevant Parties in the Syrian Transitional Government
3. Resumption of Conflict between Turkey/Syrian National Army and the Syrian Democratic Forces, and U.S. Policy Concerns
4. October 2019 Case: Turkey-led Invasion and U.S. Sanctions
5. Potential Congressional Considerations Regarding Sanctions or Other Measures
6. Broader U.S. Priorities in Syria

Document Introduction

Following the collapse of the Bashar al-Assad regime in December 2024, Turkey has become the most influential external actor in Syria, dealing a heavy blow to the regime's primary external protectors, Russia and Iran. Turkey's relationship with Hay'at Tahrir al-Sham (HTS), the U.S.-designated Foreign Terrorist Organization that led the overthrow of Assad in late 2024, is complex and multifaceted. Simultaneously, Turkey directly supports the Syrian National Army (SNA) coalition, which helped Ankara seize and maintain control over much of northern Syria from the U.S.-backed, Kurdish-led Syrian Democratic Forces (SDF), with whom it continues to engage in conflict.

The Turkish government opposes U.S. support for the SDF, seeking to weaken the People's Protection Units (YPG), which dominate the SDF, on the grounds of the YPG's links to the Kurdistan Workers' Party (PKK)—a designated Foreign Terrorist Organization that has waged a decades-long insurgency against the Turkish state. Turkey's protection of Idlib province has allowed its de facto ruler, HTS, to develop various military and political capabilities, with some reports suggesting Turkey may have also provided drones and logistical support to HTS. One of Turkey's long-standing policy pillars is to prevent further refugee influx into Turkey, which currently hosts over 3 million of the nearly 5 million Syrian refugees in the region.

In the post-Assad era, a new SNA offensive against the SDF has become the most critical recent issue in U.S.-Turkey relations. The conflict between the SNA and SDF has heightened U.S.-Turkey tensions, as the SDF has been the primary U.S. ground force partner in the fight against the Islamic State (IS/ISIS). Turkey and the SNA conducted three major military operations in 2016, 2018, and 2019 in response to the YPG's successive control over much of Syria's northern border region in the mid-2010s, replacing YPG rule in these areas with Turkish-backed Syrian forces.

Senior Biden administration officials have engaged with Turkish and SDF-related parties in an attempt to prevent further escalation of conflict, which could undermine U.S. military support for the SDF's efforts to combat ISIS remnants and manage detention facilities and camps holding ISIS-affiliated individuals. In the December 2024 fighting, the SNA, with Turkish air support, captured the towns of Tal Rifaat and Manbij from the SDF along key transportation routes, while tensions escalated among all parties in the Kobani region.

In October 2019, following then-U.S. President Trump's order for U.S. troops to withdraw from northern Syria, Turkey launched a ground invasion into areas then controlled by U.S.-backed SDF/YPG forces. The Trump administration imposed sanctions on Turkey for nine days, later lifted under a U.S.-Turkey ceasefire agreement. The fall of Assad and the concentration of Russian forces at bases in western Syria appear to have removed potential constraints on possible conflict between Turkish/SNA and SDF/YPG forces.

Congress may evaluate options regarding sanctions on Turkey, arms sales, foreign assistance, and authorizations or appropriations related to U.S. military operations. Considerations may include the anticipated potential withdrawal order from President-elect Trump, HTS's stance on Kurdish rights, the feasibility of various parties assuming counterterrorism responsibilities, and broader U.S. priorities in Syria.