Summary
The Syrian Democratic Forces (SDF) were central to defeating ISIS, serving as the U.S.’s primary ground partner in northeastern Syria through combat operations, local governance, and management of detainees. Yet their battlefield success did not translate into lasting political or strategic leverage. As ISIS lost territory, and interim authorities in Damascus began presenting themselves as an alternative power, the SDF faced marginalization, failed integration negotiations, and the absence of durable international guarantees.
Their experience underscores the limits of transactional counterterrorism partnerships: operational victories alone cannot secure post-conflict protection or influence. The SDF case highlights a critical lesson for policymakers, alliances with non-state actors must include robust political frameworks to ensure long-term stability, prevent security gaps, and maintain credibility.
The SDF and the Defeat of ISIS
The Syrian Democratic Forces (SDF) emerged during the Syrian civil war as an effective multi-ethnic military coalition, predominantly Kurdish-led but inclusive of Arab and other fighters. Their role evolved from local defense to becoming the primary on-the-ground partner of the United States and the broader anti-ISIS coalition in northeastern Syria.
From 2014 onward, as ISIS established its so-called “caliphate,” the SDF became the principal force confronting the group in key territorial battles. Their operational partnership with the U.S.-led coalition was central to dismantling ISIS’s territorial control. Coalition forces regularly conducted joint operations with the SDF against ISIS cells and strongholds, bolstering counterterrorism effectiveness across northern and eastern Syria.
In sustained operations, U.S. Central Command (CENTCOM) credited the SDF with assisting in multiple counter-ISIS missions, including the capture of senior ISIS figures and the recapture of escaped militants from detention facilities.
Beyond combat, the SDF managed hundreds of ISIS detainees in facilities such as al-Hol, holding thousands of fighters and family members. Pentagon officials confirmed that U.S. cooperation with the SDF focused primarily on defeating ISIS, underscoring the tactical nature of the partnership.
Tactical Partnership Without Strategic Guarantees
While operationally effective, the U.S.-SDF partnership was tactical rather than embedded in a durable strategic framework. Its focus on defeating ISIS lacked mechanisms to protect the SDF’s post-ISIS political standing or security autonomy.
U.S. officials consistently framed cooperation narrowly around counterterrorism, emphasizing that the alliance was justified by defeating ISIS, not broader political commitments. The SDF’s strategic dependence on U.S. support did not translate into formal political guarantees or long-term security frameworks.
Efforts to integrate the SDF into Syria’s national security architecture focused on institutional integration rather than autonomous protection. A 2025 agreement envisaged restructuring Kurdish military and civilian structures under Damascus’s authority; a framework prioritizing state sovereignty over SDF autonomy.
Victory Without Leverage
Paradoxically, the SDF’s success became a source of vulnerability. With the ISIS threat diminished, U.S. policymakers increasingly viewed northeast Syria as a stabilization challenge rather than an active battlefield. Control over ISIS detainees and camps, once a strategic asset, became a liability. The SDF assumed responsibility for tens of thousands of ISIS fighters and family members in al-Hol and al-Roj camps, without corresponding international guarantees.
Additionally, the absence of a post-ISIS political framework meant the SDF’s territorial control never translated into recognized authority. Unlike state actors, they lacked sovereignty, diplomatic recognition, or institutional backing to secure wartime gains. As U.S. officials reiterated that permanent autonomy arrangements were not supported, the SDF’s negotiating leverage declined.
The Process of Marginalisation
The SDF’s sidelining has been a gradual process shaped by military, political, and diplomatic factors. Integration negotiations with Damascus repeatedly faltered, with talks failing to deliver durable frameworks for SDF autonomy. Despite months of dialogue, clashes erupted in key cities like Aleppo.
Government forces expanded into areas formerly controlled by the SDF, including Al-Hasakah and sieging Kobani. Escalating clashes and ceasefire violations raised concerns about the security of ISIS detention facilities. State narratives increasingly framed the SDF as a threat to national sovereignty rather than partners.
International actors signaled a recalibration of engagement. While the U.S. continues emphasizing counter-ISIS collaboration, the SDF’s long-term political or security guarantees remain absent.
Strategic Implications
InThe sidelining of the SDF carries wide-ranging implications for U.S. counterterrorism credibility, ISIS containment, proxy warfare, and regional dynamics. First, it raises questions about the credibility of U.S. partnerships with non-state actors. By demonstrating that local partners who bear the primary operational burden can be politically sidelined once immediate objectives are achieved, the SDF case reinforces the perception that such alliances are transactional and short-term, potentially discouraging future cooperation (International Crisis Group).
Second, the risk to ISIS containment is significant. The SDF continues to guard thousands of fighters and family members in detention facilities such as al-Hol and al-Roj, a responsibility critical to preventing extremist resurgence. Without sustained political and security guarantees, however, this custodial role becomes unstable, increasing the potential for ISIS to reorganize or escape confinement.
Third, the SDF’s experience highlights lessons in proxy and partner warfare. Operational success does not automatically secure political protection. Research from RAND emphasizes that non-state partners require robust post-conflict frameworks to convert battlefield effectiveness into long-term stability; absent such frameworks, military gains can leave partners exposed (RAND).
Finally, the marginalization of the SDF carries regional signal effects, demonstrating a preference for centralized state authority over decentralized governance models in Syria and potentially influencing how local actors weigh alliances with external powers. Collectively, these implications underline a key lesson: operational victories without accompanying political frameworks risk achieving short-term success at the expense of long-term stability, credibility, and security.
Conclusion
The SDF experience demonstrates that military success alone does not guarantee political protection. Despite their central role in defeating ISIS, their subsequent marginalization highlights the structural limits of alliances built on narrowly defined security objectives. This is not a moral tale of betrayal but a structural lesson: counterterrorism partnerships must balance operational effectiveness with political sustainability. Short-term victories without durable political architecture create strategic fragility, erode credibility, and leave gaps in post-conflict security. The SDF’s case underscores that success in the field is insufficient if not paired with mechanisms capable of translating military gains into lasting stability.
Written by Binar Faeq Karim, Associate Fellow at CISES.