The primary responsibility of the Security Council under the Charter of the UN is maintenance of international peace and security. In order to ensure the rights and benefits resulting from membership to all Members, all of them must fulfil the obligations assumed in accordance with the Charter.
When a complaint concerning a threat to peace is brought before it, the Council's first action is to recommend to the parties to try and reach agreement by peaceful means. In some cases, the Council itself undertakes investigation and mediation. When a dispute leads to fighting, the Council's first concern is to bring it to an end as soon as possible. It often sends UN peacekeeping forces to help reduce tensions in troubled areas, keep opposing forces apart and create conditions of calm in which peaceful settlements may be sought. The Council may decide on enforcement measures, economic sanctions (such as trade embargoes) or collective military action (Chapter VII of the Charter). In some cases, the Council may authorise its Members to use “all necessary means,” including collective military action, in order to carry out the Council’s decisions.
The Council has 15 members - five permanent members (China, France, Russian Federation, United Kingdom and United States) and 10 elected by the General Assembly for two-year terms.
Each Council member has one vote. Decisions on procedural matters are made by an affirmative vote of at least nine of the 15 members. Decisions on substantive matters require nine votes, including the concurring votes of all five permanent members. If a member does not agree with a Council’s decision, may cast a negative vote, which is often referred to as the "veto" power. All 5 permanent members have exercised this right in the past. If a member does not agree with a Council’s decision, but does not wish to block the decision by using a veto, it may abstain from voting.
A UN member state that is not a Council member may take part in the discussions that concern it, but does not have the right to vote.