This article examines how the tension between the state’s right to sovereignty and the human rights of protected populations shapes integration under conditions of mass, temporary-protection-based migration. Over the past decade, Türkiye has become one of the principal countries granting temporary protection to millions of people, and what was initially treated as a short-term measure has gradually hardened into a condition bordering on permanence. Drawing on a qualitatively driven, mixed-methods field study carried out over roughly seven years in Ankara, Istanbul, and Kocaeli, the article analyses the experiences of both protected individuals and the host society through in-depth interviews, informal conversations, and sustained observation. Its central claim is that sovereignty and human rights are not opposing forces but principles that meet on common ground—the ground of legitimacy. The findings identify legal uncertainty as the single most decisive obstacle to integration and reveal a feedback loop in which legal certainty, fair treatment, and a sense of security generate legitimacy; legitimacy fosters trust; trust enables integration; and integration, in turn, underpins social stability. Trust is examined at the institutional, societal, and interpersonal levels, and stability through indicators of public order, social cohesion, and perceived justice. On this basis, the article proposes a Legitimacy-Based Model of Temporary Protection and Sustainable Return. The model ties the durability of a protection regime not to its length but to legal certainty, to a two-sided legitimacy earned simultaneously in the eyes of the host society and the protected individual, and to a predictable horizon of return that is safe, voluntary, dignified, and lawful—conceived together with the reconstruction of countries of origin and broad international cooperation. Rather than denying or inflaming the host society’s concerns about stability, the approach sustains protection while preparing for eventual return. The findings are translated into an integrated reform package spanning legal, ethical, institutional, social, and international layers, with institutional memory, resilience, and ethical leadership as its load-bearing conditions. The study thus shows that social stability and individual dignity are not opposites but two faces of a single solution, and offers a framework that reconceives integration not solely in terms of “staying” but along the axis of a legitimate and sustainable return.