The United Nations Security Council (UNSC) is an important global peace and security means. However, its efficacy has come under question, especially in Ukraine. This paper studies the structure limits, political limits, and operational challenges of the UNSC's response to the Ukraine crisis. Results indicate that the vetoes of those permanent members, especially Russia, have hampered decisive action. The UNSC has resolutions and diplomatic efforts but has been unable to force its way into peace, and this has shown weak spots in multilateral diplomacy. In addition, regional parties and NGOs had stepped in to perform conflict management, gradually building their roles and partially replacing the deficiencies of the UNSC. This paper argues that the Council's effectiveness can be improved through structural reforms such as limiting the use of vetos in humanitarian crises. The findings contribute to ongoing debate on whether multilateral diplomacy is going in the right direction, that is, toward a more responsive and adaptable UN framework.