By Adam Weinstein and Steven Simon
Executive Summary:
The U.S.–Türkiye relationship today is a fraught partnership marked by discord and strategic misalignment — particularly within the context of the Syrian Civil War but long before it as well. With the fading of old irritants in a post–Assad Syrian political landscape, a more stable and cooperative U.S.–Türkiye relationship is possible — an opportunity the Trump administration should seize.
The United States and Türkiye, though NATO allies, have historically lacked the shared values that make the transactionalism inherent in alliance frameworks easier to manage. As such, tensions have arisen when the strategic interests of each country or domestic politics have diverged. The Syrian Civil War, particularly since the emergence of the ISIS caliphate in 2014, illustrated this division starkly.
While initially supportive of the mission to defeat ISIS in Syria, Türkiye became disillusioned with the military campaign once the United States partnered with the Kurdish–led People’s Protection Units, or YPG. To Türkiye, the YPG is an extension of the Kurdistan Workers Party, or PKK, a militant Kurdish group that the country has fought since the early 1980s and views as an existential challenge. This misalignment of primary objectives in Syria created a fraught dynamic between the U.S. and Türkiye.
In December 2024, Bashar al–Assad’s regime fell following a successful military campaign by Hay`at Tahrir al–Sham, or HTS, a Sunni Islamist group with close ties to Türkiye. While HTS’s rule moving forward is precarious, the United States and Türkiye share a common interest in preventing renewed civil strife in Syria. A resumed war could create another wave of asylum migration to Türkiye and beyond, stimulate deeper Israeli involvement, renew Iranian attempts to influence developments, and run counter to a broadly shared international interest in a unitary Syrian state.
President Trump has expressed a desire to withdraw American troops from Syria and a willingness to permit greater Turkish influence in northern Syria.
To advance a more cooperative U.S.–Türkiye relationship, this brief recommends the following:
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The Trump administration should establish a formal working group with Türkiye on Syria, bringing together intelligence, military, diplomatic, and economic channels.
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Türkiye and Kurdish groups should engage in backchannel diplomacy to promote Kurdish integration into a functioning Syrian state and protect the Kurds against human rights abuses.
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The United States and Türkiye should rebuild strategic trust through targeted defense cooperation, resuming U.S. arms sales to Türkiye contingent on its cooperation in Syria and Iraq, and expanding U.S.–Türkiye joint training and NATO exercises.
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Türkiye and Israel should engage in stabilization dialogue to mitigate tensions over their respective zones of influence in Syria and to coordinate on eastern Mediterranean energy development.
Introduction
During the Cold War, U.S.–Türkiye relations were anchored in their shared NATO alliance and mutual distrust of the Soviet Union. Today, headlines about tensions between Washington and Ankara often focus on Türkiye’s balancing act between the United States and Russia. In particular, Ankara maintains deep economic ties with Moscow, even as Washington has until recently remained committed to Russia’s military defeat in Ukraine. But the more consequential fractures in the relationship have emerged in the Middle East.
A major turning point came in 2003, when Türkiye’s parliament refused to allow U.S. troops to launch the Iraq invasion from Turkish soil. Still, Türkiye contributed noncombat forces to Afghanistan and was initially embraced by the Obama administration as a model of democratic Islamism for the region. However, the emergence of the Islamic State organization, or ISIS, exposed irreconcilable differences in priorities. The United States helped mobilize the Syrian Democratic Forces, or SDF — dominated by the People’s Protection Units, known by the Kurdish acronym YPG, a predominantly Kurdish Syrian militia — to defeat ISIS without deploying large numbers of American ground troops.
But for Türkiye, the YPG is inseparable from the Kurdistan Workers Party, known by the Kurdish acronym PKK, which is designated as a terrorist organization by both Ankara and Washington. The PKK occupies a similar place in Türkiye’s national security mindset as al–Qaeda does for the United States, except the former group has an even longer and bloodier history of attacks inside the country. Additionally, the PKK also engenders the added fear, from Ankara’s perspective, that it could eventually fracture the country through the secession of the Kurdish–majority southeast, a region that has seen intense urban warfare as recently as the past decade.
A fraught partnership: U.S.–Türkiye tensions amid divergent Middle East priorities
U.S.–Türkiye strategic misalignment
The U.S.–Türkiye relationship is marked by mutual distrust, a lack of shared purpose, and, in Türkiye, notable public resentment. The relationship remains largely transactional, raising numerous questions: Is this model sustainable? What would follow if the United States withdrew from Syria? How can Washington assure Ankara that it does not back any Kurdish threat to Türkiye’s territorial integrity or the foundations of its republic? Where do arms sales and the NATO partnership fit in? Can the relationship be reset?
These questions reflect the deep complexities facing U.S.–Türkiye ties in the Middle East. U.S. foreign policy often overlooks how partners and adversaries perceive their own national security interests. This blind spot, especially pronounced after U.S. interventions since the September 11 attacks in 2001, has hurt relations with Türkiye. Washington has failed to fully grasp how seriously Ankara has viewed the PKK — not only as a threat but as a national trauma.
By drawing semantic lines between the SDF, YPG, and PKK, the United States deepened suspicion and fueled conspiratorial thinking in Türkiye. From Ankara’s perspective, Washington’s defense of partnering with its archenemy amounts to diplomatic gaslighting. From the perspective of Turkish officials, if these groups were truly separate, as Washington formally claims, then the United States should assist Türkiye in defeating the PKK.
Strategic and regional costs of U.S.–Türkiye discord
The long-standing U.S. concern about the costs of discord has focused on the risk of horizontal escalation by Ankara. Thus, Washington habitually worries that bilateral disputes about Middle Eastern issues, usually relating to Kurdish and Turkish security, would tempt Ankara to coerce Washington by imposing costs within the NATO arena or, conversely, using pressure on the Syrian Kurds as leverage in Brussels. As a practical matter, the first of these reciprocal dynamics is the one that has generated the greatest anxiety in Washington.
A careful look at the record of the past five years, however, reveals that both Türkiye and the United States see it as in their interest to wall off disputes in one theater from business in the other (see Appendix). In most years, compartmentalization was achieved, with tensions in Syria and Iraq not fully disrupting NATO relations. The exception was 2019 (and the years leading up to it), when Türkiye’s incursion into Syria and NATO veto threats led to direct spillover, breaking down the separation between arenas. Otherwise, the United States and Türkiye have generally shown a consistent ability to disagree intensely in one domain while cooperating or managing in the other. Thus, although prudence in a delicate alliance is always appropriate, both countries have worked to ensure that the costs of discord are contained and effectively managed.
Finding future common ground
Both the United States and Türkiye share an interest in a stable Syria. A weak state radiating violence would certainly threaten Turkish security, as an uptick in ISIS’s infiltration in the country already suggests. It would also threaten the U.S. investment in Iraq, which only now appears to be paying off, and could trigger diplomatic and possibly military clashes between Israel and Türkiye. The United States and Türkiye both have an interest in resolving the status of Kurds within Syria. Turkish objectives have been clear and consistent over time, geared to the suppression of Kurdish bids for autonomy within Syria. Ankara’s anxiety on this score might have been alleviated, at least to a degree, by the PKK’s unilateral decision to lay down its arms and Syrian Kurdish negotiations with the transitional government in Damascus.
U.S. objectives have been less clear-cut. U.S. troop deployments within Syria are closely intertwined with the security of Syrian Kurds vis-à-vis a predatory Turkish neighbor. Türkiye has been prepared to risk a confrontation with the United States, as evidenced by artillery strikes against bases in Syria where U.S. troops and SDF personnel are colocated and by engagement with Kurdish forces directly and through proxy militias.
Conclusion
Despite being NATO allies, the United States and Türkiye lack deep cultural, historical, or people-to-people ties. Their relationship is shaped by strategic and transactional considerations. In this realm, major barriers to cooperation have been removed. The death of Fethullah Gülen in Oct. 2024, the ongoing U.S. withdrawal from northeast Syria, and the pledged dissolution of the PKK have, by Türkiye’s own assessment, removed important national security threats. This shift has coincided with the departure of some vocal, critical members of Congress. The collapse of the Assad regime, however, carries ambiguous implications for Turkish interests.
Most of these goals can be advanced by recognizing that Turkish leaders view northern Iraq and Syria as vital to their country’s national security, clearly communicating U.S. redlines, and prioritizing areas of cooperation, such as counter–ISIS efforts in post–Assad Syria and Iraq.