The United Nations has had both successes and failures in maintaining international peace and security. Among its successes, the UN has intervened to resolve crises like the Suez Crisis and Cuban Missile Crisis. It has also played an important peacekeeping role in conflicts in the Congo and the Gulf War. However, the UN has struggled to resolve long-standing conflicts in places like the Middle East, Somalia, and Rwanda. Critics argue the UN is hampered by the overuse of veto power in the Security Council and lacks an independent military force. Overall, the UN has achieved some successes but still faces challenges in fully achieving its goals of preventing war and promoting global cooperation.