Eighty years after the establishment of the United Nations, the world order has undergone fundamental transformations. This study examines the transition from a Western-centered hegemonic structure toward a multipolar order, with particular attention to the role of resistance movements and actors. It seeks to answer the central question of how the balance of power within the United Nations has shifted from unilateral dominance toward collective agency and a discourse of resistance. The study employs a qualitative research approach based on discourse analysis and an examination of international documents, including resolutions, General Assembly statements, and Security Council reports, covering the period from 2000 to 2025. The findings indicate that the emergence of rising powers, the declining effectiveness of veto mechanisms, and the increasing voice of countries from the Global South have contributed to the emergence of resistance dynamics against the Western-led liberal order. These developments have transformed multilateralism from a normative aspiration into a more operational reality on the United Nations agenda, although this transformation has been accompanied by structural tensions and ongoing contestation over the meaning and scope of national sovereignty. Ultimately, the article argues that, as the United Nations approaches its ninth decade, it faces an increasing need to reconsider the foundations of its legitimacy, representativeness, and effectiveness in light of the emergence of a multipolar order and evolving dynamics of resistance.