Which UN body has the authority to make decisions that all member states are obligated to carry out?

The Security Council has the authority to make decisions that all member states are obligated to carry out. This power is grounded in the United Nations Charter, which grants the Security Council the responsibility to maintain international peace and security. When the Security Council passes resolutions, particularly those under Chapter VII of the Charter, these decisions are binding on member states, meaning they must comply with the directives given. This is crucial for the enforcement of collective security measures, such as sanctions or military action, aimed at addressing threats to peace or acts of aggression.

In contrast, the General Assembly, while it allows for deliberation and the passing of resolutions, does not have the same binding authority on member states. The Secretariat provides administrative support to the UN and does not have legislative power. The International Court of Justice serves as the principal judicial body of the UN but primarily deals with legal disputes between states and issues advisory opinions; its decisions are not enforceable in the same manner as those of the Security Council.