South Africa is a constitutional democracy with a three-tier system of government and an independent judiciary. The national, provincial and local levels of government all have legislative and executive authority in their own spheres, and are defined in the Constitution as "distinctive, interdependent and interrelated". Operating at both national and provincial levels are advisory bodies drawn from South Africa's traditional leaders. It is a stated intention in the Constitution that the country be run on a system of co-operative governance. Parliament Legislative authority is vested in Parliament, which is situated in Cape Town and consists of two houses, the National Assembly and the National Council of Provinces.