National politics in Cambodia take place within the framework of the nation's constitution of 1993. The government is a constitutional monarchy operated as a parliamentary representative democracy. The Prime Minister of Cambodia, an office held by Hun Sen since 1985, is the head of government, while the King (currently Norodom Sihamoni) is the head of state. The Prime Minister is appointed by the King, on the advice and with the approval of the National Assembly
The Prime Minister and the ministerial appointees exercise executive power while legislative powers are shared by the executive and the bicameral Parliament of Cambodia, which consists of a lower house, the National Assembly or Radhsphea and an upper house, the Senate or Sénat. Members of the 123-seat Assembly are elected through a system of proportional representation and serve for a maximum term of five years. The Senate has 61 seats, two of which are appointed by the King and two others by the National Assembly Senators serve five year terms.
On October 14, 2004, King Norodom Sihamoni was selected by a special nine-member throne council, part of a selection process that was quickly put in place after the abdication of King Norodom Sihanouk a week prior. Sihamoni's selection was endorsed by Prime Minister Hun Sen and National Assembly Speaker Prince Norodom Ranariddh (the king's half brother and current chief advisor), both members of the throne council. He was enthroned in Phnom Penh on October 29, 2004.
The Cambodian People's Party is the major ruling party in Cambodia. The CPP controls the lower and upper chambers of parliament, with 73 seats in the National Assembly and 43 seats in the Senate. The opposition Sam Rainsy Party is the second largest party in Cambodia with 26 seats in the National Assembly and 2 in the Senate.