Postwar political parties in Greece centered more on leaders than platforms. The Greek Rally, founded and led by Field Marshal Alexander Papagos, won control of the government in the 1951 elections. About 10% of the vote was received by the Union of the Democratic Left, a left-wing party founded in 1951 as a substitute for the Communist Party, outlawed since 1947. When Papagos died in October 1955, Constantine Karamanlis formed a new party called the National Radical Union, which won the elections of 1956, 1958, and 1961 and held power until 1963, when Karamanlis resigned and the newly formed Center Union, comprising a coalition of liberals and progressives and led by George Papandreou, subsequently won a narrow plurality, with Papandreou becoming prime minister. In elections held in February 1964, the Center Union won 174 out of 300 seats; however, King Constantine dismissed Papandreou in July 1965, and Stephanos Stephanopoulos formed a new government. This government, too, was short-lived. Political conflict came to a head when Panayotis Kanellopoulos, leader of the National Radical Union, who had been appointed premier of a caretaker government, set new elections for 28 May 1967. On 21 April, however, a military coup resulted in the cancellation of elections and suppression of political parties, which lasted until 1974.
On 28 September 1974, following his return from exile, Karamanlis formed the New Democracy Party (Nea Dimokratia—ND), advocating a middle course between left and right and promoting closer ties with Western Europe. The Center Union–New Forces (EKND), renamed the Union of the Democratic Center (EDHK) in 1976, rallied liberal factions of the former Center Union and announced a line that generally paralleled ND policies. The EDHK disintegrated following the 1981 elections. Other groups to emerge, most of them led by former opponents of the junta, included the Pan-Hellenic Socialist Movement (Panellinio Socialistiko Kinema—PASOK), led by Andreas Papandreou; the United Left (UL), which brought together elements of the Union of the Democratic Left and the Communist Party to oppose the upcoming elections; and the National Democratic Union (NDU), which represented an amalgam of various elements, including some royalists and right-wing activists. Also in 1974, the Communist Party (Kommounistiko Komma Ellados—KKE) was made legal for the first time since 1947; the party later split into two factions, the pro-Soviet KKE-Exterior and the Eurocommunist wing, called the KKE-Interior. In May 1986, the KKE-Interior changed its name to the New Hellenic Left Party.
In the general elections held on 17 November 1974, the ND won an overwhelming majority in parliament, with the EKND forming the major opposition. The ND was again the winner in 1977, although its parliamentary majority dropped from 220 to 172. After parliament elected Karamanlis president in 1980, George Rallis succeeded him as prime minister. In the elections of 18 October 1981, Papandreou's PASOK won 48% of the popular vote and commanded a clear parliamentary majority. Although PASOK won again in the election of 2 June 1985, its share of the total votes cast fell to 45.8%.
In the elections of 10 October 1993, PASOK had about the same percentage (46.9%) and a majority of 171 seats. The ND followed with 110 seats and an offshoot party, Political Spring, had 10 seats. The Communists gained 9 places.
In the parliamentary elections of 22 September 1996, PASOK retained it majority, but lost nine seats. ND emerged with 108 seats; the KKE, 11; Coalition of the Left and Progress, 10; and the Democratic and Social Movement Parties, 9. The Political Spring lost all its seats in the election, gaining only 2.95% of the popular vote.
PASOK continued its dominance of the post-1974 era with yet another victory at the polls on 9 April 2000. In a close election PASOK won 158 seats (43.8% of the vote), ND earned 125 seats (42.7%), the KKE held steady at 11 (5.5%), while the Coalition of the Left and Progress saw its share of the seats drop to 6 (3.2%). The Democratic Social Movement failed to clear the 3% hurdle needed for representation and Political Spring once again failed to win any seats.