Until 1992, the Republic of the Congo was governed under a constitution, approved by referendum on 8 July 1979 and amended in July 1984. The chairman of the 75-member Central Committee of the Congolese Labor Party (PCT) was the president of the republic and head of state. He was elected for an unspecified term as chairman (and therefore as president) by the party congress. Executive powers resided with the Council of Ministers, appointed by the prime minister and chaired by the president. The 153-member National Assembly, the sole legislative body, was elected by universal suffrage at age 18 from candidates named by the PCT.
On 15 March 1992, voters approved a new constitution, which provided for a mixed presidential-parliamentary form of government after the French model. Executive authority is vested in a directly elected president, who appoints the prime minister and cabinet. A National Assembly of 125 members was elected in two-round elections in June and July 1992. There was also a 60-member Senate. Pascal Lissouba was chosen president (61%) and his Pan-African Union for Social Democracy (UPADS) gained 39 seats. That legislature was dissolved in October and new legislative elections in May 1993 led to partisan fighting. A mediated settlement then confirmed a UPADS majority, yet fighting continued into 1994. In the view of many, the "democratic election" was the catalyst that unleashed tribal hatreds.
Soon after the defeat of Lissouba in the four-month 1997 civil war, Sassou-Nguesso formed a transitional government and replaced the 1992 constitution with a Fundamental Act. The Act gave additional powers to the executive making the president head of state and government, commander in chief of the armed forces with powers to appoint all members of the government, all senior military officers and government officials at sub-national level. He was also mandated to direct the general policy of the government and to exercise regulatory powers.
In 1998, Sassou-Nguesso appointed a committee to draft a new constitution, which eventually was approved by national referendum in January 2002. The next presidential elections were scheduled for 2009 and legislative elections for 2007.