This thesis investigates the ethical and structural dimensions of the United Kingdom and United States (US) governments’ continued control over the Chagos Archipelago. Using a dual theoretical framework of Giorgio Agamben’s Homo Sacer and David Held’s Cosmopolitanism, the study aims to critically examine how the maintenance of non-sovereign territories undermines global governance norms. Methodologically, a Most Similar Systems Design is employed to compare Diego Garcia with other US-controlled territories: Guam, Puerto Rico, and American Samoa, exposing failures not only in the ethical governance of the UK and US but also in the responses of international institutions toward the Chagossians. Fairclough’s three-dimensional model of Critical Discourse Analysis is used to analyze the proposed agreement between the UK and Mauritius and its consequences. The findings suggest that historical injustices have been perpetuated through continued indifference toward Chagossians' voices and broader patterns of systemic violence. The thesis concludes that powerful states maintaining control over extraterritorial zones undermine international institutions' accountability. To guarantee justice in postcolonial contexts, the thesis advocates for the United Nations and International Court of Justice reform according to Held's cosmopolitan ideals.