The Cook Islands are governed under the constitution of 1965. The monarch of Great Britain and Northern Island is the head of state and appoints a British representative. The prime minister heads the government. There is a bicameral parliament. Members of the 25-seat Legislative Assembly are elected by popular vote for five-year terms. The 15-member House of Ariki (hereditary chiefs) is a purely consultative body that advises on traditional matters. New Zealand, represented by a high commissioner, is responsible for foreign affairs and defense in consultation with the Cook Islands government.