Under the 2010 constitution, Tonga is a constitutional monarchy and a parliamentary democracy. The monarchy is hereditary, and the monarch is head of state. Until 2010, the constitution was essentially King George Tupou I’s constitution granted in 1875, under which executive power resided with the monarch.

The unicameral legislature is the Legislative Assembly which comprises 26 elected members, nine of whom are elected by and from among the country’s 33 hereditary nobles, and 17 on the basis of universal adult suffrage. General elections must take place at least every four years.

The head of government is the prime minister, who is chosen by the Legislative Assembly and appointed by the monarch. The prime minister selects the cabinet who are then appointed by the monarch. The prime minister may nominate up to four members from outside the Assembly and on appointment they become members of the Assembly.

All land belongs to the Crown. Large estates have been allotted to nobles. By law, every male Tongan at age 16 is entitled to a small piece of agricultural land and a small town plot. In practice, there is not enough land, and the reform of the land tenure system is currently under discussion.

The Court of Appeal is presided over by the chief justice and its three other members are judges from other Commonwealth countries. It is the final court of appeal. The Supreme Court and the Land Court are also presided over by the chief justice, with one Tongan judge the other member in both cases. Litigants before the Supreme Court, in both civil and criminal cases, may opt for trial by jury. Appeals from the eight magistrates’ courts are heard by the Supreme Court.