Under the 1988 Constitution the country is a federal republic comprising 26 states and a Federal District (Brasilia). Legislative power is exercised by the bicameral Congresso Nacional (National Congress), comprising the Senado Federal (Federal Senate—members elected by the majority principle in rotation for eight years) and the Câmara dos Deputados (Chamber of Deputies—members elected by a system of proportional representation for four years). Executive power is exercised by the President, elected by direct ballot for four years.