On 12 July 1975, São Tomé and Príncipe, formerly considered overseas territories of Portugal, became an independent democratic republic. The constitution, drafted by a constituent assembly, took effect on 12 December 1975. The president was chief of state, elected by the 40-member People's Assembly for a term of four years. The prime minister, who was elected to a five-year term by the People's Assembly on the recommendation of the MLSTP, appointed and headed the cabinet. District popular assemblies elected in August 1985 chose the members of the People's Assembly, which elected Pinto da Costa to a third term as president on 30 September 1985. The MLSTP had been the sole legal political party until 1990. A new constitution was announced by da Costa in 1989 and adopted by the People's Assembly in April 1990 and approved in an August referendum and went into force in September 1990.
The president is chosen by a multiparty election for a maximum of two five-year terms. The prime minister is chosen by the People's Assembly and approved by the president. The Assembly, now composed of 55 members, is elected to four-year terms in twelve multi-member constituencies by proportional representation, in multiparty elections. Suffrage is universal at age 18. The next presidential and parliamentary elections were scheduled for 2006.
The power-sharing configuration of government presents a pattern for political conflict that appears to be well-established. Under the country's semi-presidential system, the president must form a government with the opposition. The president stated that he would revise the constitution to give the head of state more power, but the battle has been bloody. In September 2002, de Menezes was forced to make a change in prime minister, and when parliament attempted to strip him of his powers, he dissolved it in January 2003, a decision he subsequently reversed.