Since the outbreak of the Syrian civil war in 2011, the conflict has remained a persistent source of tension in US–Türkiye relations despite their NATO alliance. Divergences over Kurdish armed groups, military interventions, and sanctions have entrenched a structural security dilemma. The collapse of the Assad regime in late 2024 marked a critical turning point, prompting Türkiye to recalibrate its Syria policy from pursuing regime change to shaping post-conflict order. Concurrently, the re-election of Donald Trump introduced a more transactional diplomatic style, providing new policy coordination space between Washington and Ankara. In the post-Assad context, the two countries have increasingly engaged in issue-based cooperation, particularly in security governance and reconstruction efforts. However, the depth and sustainability of this cooperation remain uncertain, contingent on the interaction between US transactional diplomacy and Türkiye’s evolving role as a regional geopolitical intermediary.
Ye et al. (2026) studied this question.