Membership of the United Nations Security Council is held by the five permanent members and ten elected, non-permanent members.
Being elected requires a two-thirds majority vote from the United Nations General Assembly. Elected members hold their place on the council for a two-year term, with five seats contested in even years and five seats contested in odd years. An outgoing member cannot be immediately re-elected.
Elections usually begin in June for a term starting January 1. Because of the two-thirds majority requirement, it is possible for two evenly matched candidates to deadlock with approximately half the vote each, sometimes needing weeks of negotiations to resolve.
Non-permanent seats are distributed geographically, with a certain number of seats allocated to each of the five United Nations Regional Groups.