As NATO approaches its 2026 Ankara Summit, the alliance faces its most demanding transformation since the end of the Cold War. Türkiye’s role within NATO has undergone a fundamental strategic shift, from a southeastern flank state providing territorial depth to a central, operationally indispensable ally shaping the alliance’s deterrence posture, institutional direction, and crisis management capacity. Drawing on Türkiye’s sustained operational contributions, its 360-degree security approach, and its demonstrated capacity to project force and exercise command at scale, the commentary contends that the Ankara Summit represents a defining moment, one at which this repositioning must be reflected in the alliance’s political and institutional frameworks. It also issues a clear warning: the European Union’s exclusionary approach to non-member NATO allies risks inflicting strategic damage on Euro-Atlantic security that would exceed even the consequences of reduced American force presence on the continent.