Throughout the 1960s, despite anticolonial movements in Portugal's colonies, Salazar was still firmly in power until his death in 1968. The National Union continued to hold power very firmly, and there was little if any meaningful opposition. After Salazar's death, however, the National Union's grip over the country and in particular the military steadily weakened. In particular, the wars to hold the colonies created dissent in the ranks of the military.

On April 25, 1974, there was a military coup by a group calling themselves the Movimiento das Forcas Armadas, or Movement of the Armed Forces (MFA). The MFA consisted mostly of middle-ranked officers in the military that were stationed in Portuguese colonies and realized that the war in the colonies was one they couldn't win. The MFA was organized and led by Major Otelo Saraiva de Carvalho, but the current government refused to hand over the government to such a low-ranking officer. The government leaders would surrender only to the highest ranking officer in the MFA, General Antonio Spinola. Spinola served as the president in the provisional government that was set up. On May 15, 1974, a cabinet was set up, representing every major political group in Portugal, with a law professor named Adelino de Palma Carlos as its Prime Minister.

Two months later, Palma Carlos resigend as Prime Minister over internal disputes, and Spinola appointed Vasco Goncalves, a former member of the Communist Party, to succeed him. These disagreements between the parties involved grew more intense over the summer, leading Spinola to resign as president. Throughout the fall and winter, the infighting grew worse, as the MFA and the Goncalves government became more radical, while the Socialist Party fought against this radicalization. Despite this unstable governmental situation, on April 25, 1975, the first free elections based on universal suffrage were held, and went off without problems.

In the election, the Socialist Party emerged as the strongest party, followed by the People's Democratic Party. Afterwards, the Socialist Party came out strongly against the rule of the MFA. In September, Prime Minister Goncalves was forced to step down, and a broad coalition government was created once again under Admiral Pinheiro de Azevedo. On November 25, however, a coup attempt by some left-wing members of the MFA was defeated by a counter-coup under the leadership of Colonel Antonio Ramalho Eanes.

On April 25, 1976, new elections were held, confirming the strength of the Socialist Party. On July 27, Ramalho Eanes was elected President with 61.5 percent of the votes. Otelo Saraiva de Carvalho, the original leader of the MFA, finished second with 16.5 percent, followed by Prime Minister Pinheiro de Azevedo with 14.4 percent.

A Socialist government was formed under Prime Minister Mario Soares, which immediately went about trying to stabilize the economy. This minority government fell apart a year later, and a coalition between the Socialists and the Social Democratic Center formed a majority government which lasted for half a year. For the following year and a half, several governments appointed by Ramalho Eanes held power before elections were held in 1979.

In this election, a coalition was formed between the Social Democratic Center, Social Democratic Party, and People's Monarchic Party; these parties presented common candidates as the Democratic Alliance. This coalition did very well, but was unable to establish a very stable government. In 1980, Ramalho Eanes was reelected and the Democratic Alliance gained support. In 1982, a new Constitution was adopted, although the majority of Portuguese people were not aware that this happened.

In 1983, the Democratic Alliance broke apart, and the Socialists emerged as the strongest party. Mario Soares quickly formed a government with the Social Democratic Party, although this coalition broke down when it was announced that Soares would be running for president in 1986. In 1985, the Socialists lost much support while the Social Democratic Party was the most successful party. A new party, the Party of Democratic Renewal, was also very successful, benefiting from the tacit support of President Ramalho Eanes. The Social Democrats established a government with the support of this new party.

In 1986, Soares narrowly won the presidential election, and became the first civilian to hold the position. However, his Socialist Party continued to lose support as the Social Democrats won a majority of the legislative seats as well as a slight majority of the popular vote in the 1987 elections. Anibal Cavaco Silva continued as Prime Minister, and was immensely popular among the people. He worked well with Soares, and a relatively stable government resulted from this cooperation.

In 1991, Soares was reelected with seventy percent of the first-round votes, and Cavaco Silva retained his parliamentary majority. However, in 1992, the Portuguese economy began to deteriorate and the government started to lose support. In 1995, Cavaco Silva resigned as Prime Minister. Later that year, the Social Democrats lost a great deal of their support, as the Socialists again emerged as the strongest party. Meanwhile, Cavaco Silva announced his intention to run for President. In 1996, Cavaco Silva lost the presidential race to Jorge Sampaio of the Socialist Party.

In 1999, the Socialist Party made further gains, falling one seat short of an absolute majority in the parliament. That party remains the strongest and still holds the presidency.

On December 13, 1999, Lieutenant-Colonel Otelo Saraiva de Carvalho, the chief organizer of the 1974 military coup and the original leader of the MFA, was put on trial for charges of terrorism. He is accused of being involved in the 1980 death of then Prime Minister Francisco Lumbrales Sa Carneiro, who died in a plane crash, which was deemed an accident at the time.

Original Parties from 1950-1962 terminating before 2000

171 National Union. This was the governing party of the Salazar regime. Following Salazar's death in 1968, the party's name was changed to the Popular National Action (ANP) in 1970 but continued to hold all seats in the Assembly. The party terminated in 1974 with the military coup, which also dissolved the Assembly until elections were held in 1975 for a constituent assembly to draw up a new constitution.

New Parties formed after 1962 but terminating before 2000

178 Union of the Socialist and Democratic Left. The Union of the Socialist and Democratic Left competed in 1979, winning one percent of the votes. In 1980, it competed in a bloc with the Socialist Party and the Independent Social Democratic Party and received four seats. It never contested another election.

179 Independent Social Democratic Party. The Independent Social Democratic Party competed in a bloc with the Socialist Party and the Union of the Socialist and Democratic Left in 1980 and received four seats. It never contested another election.

New Parties formed after 1962 and continuing to 2000

172 Socialist Party. The Socialist Party (PSP) was formed in 1973 and was led by Mario Soares, who became the first prime minister under the new constitution in 1976. It was the strongest party through the late 1970s, and Soares later became the first civilian president. Its support faltered during the 1980s and early 1990s, but since 1995 it has emerged as the strongest party, currently holding exactly half of the parliamentary seats.

173 Social Democratic Party. Formed in 1974 as the Popular Democratic Party (PPD), its name was changed in 1976. From 1979 until 1983, it headed up a strong coalition with several other parties, including the Social Democratic Center, but it struggled somewhat after that coalition broke apart. In 1987, it had a phenomenal election, winning a strong majority of the seats, a majority it held until 1995, when it lost about a third of its support. Since then, it has held steady at about a third of the popular vote and seats.

174 Communist Party. Originally founded in 1921, the Communist Party had been banned by the government as early as 1926 but continued a clandestine existence. It has consistently held about five to fifteen percent of the parliamentary seats, although its support has been dwindling in the 1990s.

175 People's Party. Originally the Social Democratic Center, the People's Party adopted its present name in 1995. A strong party in the late 1970s, it united with the Social Democratic Party from 1979 to 1982 in a government. Its support steadily declined after that, although it gained some strength in 1995 after changing its name. 

176 Democratic Movement. An extreme left party, the Democratic Movement was marginally successful in 1975, then competed with the Communist Party from 1979 through 1985. After that, its support dropped sharply, and it has all but disappeared from the Portuguese political scene.

177 Popular Monarchist Party. The Popular Monarchist is a small party whose only success was joining with the Social Democratic Party and the Social Democratic Center from 1979 to 1980. It won five seats in 1979, then six in 1980. Since then, its support has fallen to almost nothing.

1710 Democratic Renewal Party. The Democratic Renewal Party appeared prior to the 1985 elections. It was created by President Ramalho Eanes, and it was very successful in its first election, winning nineteen percent of the popular vote and 45 seats. In 1987, it won only seven seats, and it lost all of those in 1991. It hasn't won a seat since then.

Caramani, Daniele 2000. The Societies of Europe: Elections in Western Europe since 1815 (New York, NY: Grove's Dictionaries, Inc.).

Gorvin, Ian 1989. Elections Since 1945: A Worldwide Reference Compendium (Harlow, Essex, U.K.: Longman).

Keesing's Record of World Events 1995-2000 (London: Keesing's Limited).

Mackie, Thomas T. and Richard Rose (1991). The International Almanac of Electoral History (London: Macmillan Press Ltd.).

Magone, Jose M. (1997) European Portugal: The Difficult Road to Sustainable Democracy (New York, NY: St. Martin's Press, Inc.).