According to Article 1, par. 1 of the UN Charter, the first of the purposes of the UN is: "To maintain international peace and security, and to that end to take effective collective measures for the prevention and removal of threats to the peace, and for the suppression of acts of aggression or other breaches of the peace, and to bring about by peaceful means, and in conformity with the principles of justice and international law, adjustment or settlement of international disputes or situations which might lead to a breach of the peace."

When all other measures of collective security fail (such as inquiry and negotiation, conciliation, mediation), the Security Council "shall determine the existence of any threat to the peace, breach of the peace or action of aggression, and shall make recommendations, or decide what measures shall be taken … to maintain or restore international peace and security." (Article 39).

But how? What means and what machinery are available to the Security Council for maintaining international peace and security?

A distinction must be made between UN armed forces and UN peace-keeping forces, the latter of which are comprised of national armed forces commissioned by the Security Council and acting in its behalf. Article 43 calls upon all member states "to make available to the Security Council, on its call and in accordance with a special agreement or agreements, armed forces, assistance, and facilities ...necessary for the purpose of maintaining international peace and security." This force should be under the command of the Security Council. To date, no member states have concluded any special agreements which would enable the creation of a special armed force directly responsible to the Security Council.