The overriding purpose of the United Nations is the preservation of peace. When states have agreed to second forces to the United Nations either for enforcement or for peacekeeping activities, they do so through agreements which specify the administrative, financial and disciplinary arrangements that are to apply, although supreme authority rests with the Secretary General. While the decisions of the Security Council are legally binding upon all members, it must be borne in mind that the Council is made up of the representatives of the member states, who act according to instructions received from their governments. Even with North Atlantic Treaty Organisation (NATO), the problems which confront the United Nations, including command, discipline, rules of engagement and the like, are of equal significance. In both the former Yugoslavia, especially in relation to Kosovo, and in Afghanistan, NATO took over the military operations against the 'terrorists'.