The 1983 Portuguese legislative election took place on 25 April. The election renewed all 250 members of the Assembly of the Republic. The last election, in October 1980 had been won by a right-wing coalition, the Democratic Alliance (AD) and Francisco Sá Carneiro had retained office as Prime Minister with an increased majority. However, Sá Carneiro, along with other important members of the coalition, died in an aircrash only two months after the election, on 4 December 1980. Such happenings caused a massive political instability and Francisco Pinto Balsemão, a senior official of the Social Democratic Party, the largest party in the Alliance, became Prime Minister. But Balsemão lacked support from such senior members of his party as Aníbal Cavaco Silva, and several ministers resigned. Moreover, the right-wing policy was criticized by the left-wing and by the trade unions, and in February 1982, the General Confederation of the Portuguese Workers, with the support of the Communists, called for a general strike that shook the government. The wave of resignations among Balsemão's ministers continued and by the end of 1982, and also influenced by the AD's bad results in the 1982 local elections, Balsemão himself also resigned. The Social Democratic Party proposes, to President Ramalho Eanes, a government led by Vítor Crespo, but President Eanes rejects the proposal citing that the political conditions are just too deteriorated, thus he decides to dissolve the Parliament and call an election for April. Shortly after, the AD was dissolved as PSD, CDS and PPM decided to run alone. The election was won by the Socialist Party with 36%, and Mário Soares was nominated Prime Minister. However, the Socialists lacked a majority in the Assembly of the Republic and were forced to form a coalition with the Social Democrats, which achieved 27%, in what was called the "Central Bloc". Although this coalition allowed Soares to govern, several members of both parties were against it, and internal attacks led to the collapse of the coalition after less than two years. In the election that followed, the Communist-dominated United People Alliance lost 3 MPs and the Democratic and Social Center, after the dissolution of the Democratic Alliance, was now alone in the Parliament with 30 MPs, a loss of 16. The election marked the beginning of a process of bi-polarization of Portuguese politics. This was the last legislative election to be won by the Socialist Party until