The UN Security Council, in theory, possesses extensive authority to address wars, acts of aggression, and grave violations of international law.However, the Council's performance has faced fundamental challenges. Using a descriptive-analytical method, this study examines the gap between the Council's theoretical mandate in confronting emerging threats and its actual performance. The main question is to identify the structural, legal, and political obstacles that reduce the Council's efficacy and legitimacy in contemporary crises. The research hypothesis focuses on three key obstacles: the veto-based decision-making structure, ambiguity in defining a threat to peace regarding emerging threats, and the incompatibility of the Council's traditional mechanisms with the technological nature of these threats. The findings indicate that the Council's effectiveness is severely influenced by the structure of the international system, the national interests of its permanent members, and the instrumental use of the veto power; factors that have led to inefficiency, lack of transparency, double standards, and weakening of the Responsibility to Protect. The twelve-day Iran-Israel war precisely confirmed this finding: due to the political considerations of its permanent members (direct participation of the United States and the cautious silence of Russia and China), the Council suffered complete paralysis and took no effective action to condemn or stop the war. The final ceasefire was also imposed not based on a Council resolution, but by the US following a military power balance. This study demonstrates the predominance of major powers' interests over collective security and a transition from classical international law to power-based diplomacy.