Founded in 1945 after World War II by 51 countries, the United Nations is committed to maintaining international peace and security; developing friendly relations among nations based on respect for the principles of equality and self-determination of peoples; achieving worldwide cooperation to solve international economic, social, cultural and humanitarian problems; and serving as a centre for harmonizing actions by countries to achieve these goals. In the 21st century, UN programs and agencies have worked to address a host of new challenges, including devastating disasters, refugee flows and AIDS; global financial turmoil; international terrorism and violent conflict; and the continuing disparity between rich and poor nations.
The Security Council has primary responsibility, under the Charter of the United Nations, for the maintenance of international peace and security. It has fifteen members — five permanent and ten non-permanent — each with one vote. The Council is obligated to comply with its decisions. It may recommend the use of force to maintain or restore peace and security in situations where the situation threatens it. It may call upon the parties to a dispute to settle it by peaceful means and may recommend methods of adjustment or terms of settlement. It shall determine whether a situation constitutes a threat to peace or act of aggression and shall decide, by a majority of its members present and voting, on the measures to be taken for the maintenance of peace and security.
Membership in the United Nations is open to any other peace-loving state that accepts the obligations contained in the Charter and, in the opinion of the Organization, is able and willing to carry them out. The exercise of rights and privileges of membership shall be subject to review and determination by the General Assembly on the recommendation of the Security Council.