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.
The African Union uses an internal rotation system to distribute seats based on its subregions:[3][4] Aside from the Asia-Pacific Group also allocating an Arab nation seat every four years (in even years not divisible by 4), other regional groups do not have their own subregional rotation systems.
The Western European and Others Group in part contains three caucusing subgroups (Benelux, the Nordic countries, and CANZ[f]), whose candidates informally coordinate with each other.
[6][5] While this has not resulted in a stable rotation system, it effectively guarantees that both seats will never be occupied by a single subgroup at the same time.
These, combined with the 61 modern nations that have never been elected to the UNSC to date (see Non-members, below), make up the 193 current members of the UN.