United Nations System
There are 15 members of the Security Council, consisting of five veto-wielding permanent members (China, France, Russia, the United Kingdom, and the United States) and 10 elected non-permanent members with two-year terms. This basic structure is set out in Chapter V of the UN Charter. Security Council members must always be present at UN headquarters in New York so that the Security Council can meet at any time.
United Nations Security Council
In mid-1944, the delegations from the Allied "Big Four", the Soviet Union, the UK, the US and China, met for the Dumbarton Oaks Conference in Washington, D.C. to negotiate the UN's structure, and the composition of the UN Security Council quickly became the dominant issue. France, the Republic of China, the Soviet Union, the UK, and US were selected as permanent members of the Security Council; the US attempted to add Brazil as a sixth member, but was opposed by the heads of the Soviet and British delegations. The most contentious issue at Dumbarton and in successive talks proved to be the veto rights of permanent members. The Soviet delegation argued that each nation should have an absolute veto that could block matters from even being discussed, while the British argued that nations should not be able to veto resolutions on disputes to which they were a party. At the Yalta Conference of February 1945, the American, British, and Russian delegations agreed that each of the "Big Five" could veto any action by the council, but not procedural resolutions, meaning that the permanent members could not prevent debate on a resolution.