On 25 November 1973, following the bloody suppression of Athens Polytechnic uprising on the 17th, the hardliner Brigadier Dimitrios Ioannides overthrew Papadopoulos and tried to continue the dictatorship despite the popular unrest the uprising had triggered. Ioannides’ attempt in July 1974 to overthrow Archbishop Makarios, the President of Cyprus, brought Greece to the brink of war with Turkey, which invaded Cyprus and occupied part of the island.
Senior Greek military officers then withdrew their support from the junta, which collapsed. Constantine Karamanlis returned from exile in France to establish a government of national unity until elections could be held. Karamanlis worked to defuse the risk of war with Turkey and also legalised the Communist Party, which had been illegal since 1947. His newly organized party, New Democracy (ND), won the elections held in November 1974 by a wide margin, and he became prime minister.
Following the 1974 referendum which resulted in the abolition of the monarchy, a new constitution was approved by parliament on 19 June 1975. Parliament elected Constantine Tsatsos as President of the Republic. In the parliamentary elections of 1977, New Democracy again won a majority of seats. In May 1980, Prime Minister Karamanlis was elected to succeed Tsatsos as President. George Rallis succeeded Karamanlis as Prime Minister.
On 1 January 1981, Greece became the tenth member of the European Community (now the European Union). In parliamentary elections held on 18 October 1981, Greece elected its first socialist government when the Panhellenic Socialist Movement (PASOK), led by Andreas Papandreou, won 172 of 300 seats. On 29 March 1985, after Prime Minister Papandreou declined to support President Karamanlis for a second term, Supreme Court Justice Christos Sartzetakis was elected president by the Greek parliament.
Greece had two rounds of parliamentary elections in 1989; both produced weak coalition governments with limited mandates. Party leaders withdrew their support in February 1990, and elections were held on 8 April. New Democracy, led by Constantine Mitsotakis, won 150 seats in that election and subsequently gained two others. However, a split between Mitsotakis and his first Foreign Minister, Antonis Samaras, in 1992, led to Samaras’ dismissal and the eventual collapse of the ND government. In new elections in September 1993, Papandreou returned to power.
On 17 January 1996, following a protracted illness, Papandreou resigned and was replaced as Prime Minister by former Minister of Trade and Industry Costas Simitis. Within days, the new prime minister had to handle a major Greek-Turkish crisis over the Imia/Kardak islands. Simitis subsequently won re-election in the 1996 and 2000 elections. In 2004, Simitis retired and George Papandreou succeeded him as PASOK leader.
In the March 2004 elections, PASOK was defeated by New Democracy, led by Kostas Karamanlis, the nephew of the former President. The government called early elections in September 2007 (normally, elections would have been held in March 2008), and New Democracy again was the majority party in the Parliament. As a result of that defeat, PASOK undertook a party election for a new leader. In that contest, George Papandreou was reelected as the head of the socialist party in Greece. In the 2009 elections however, PASOK became the majority party in the Parliament and George Papandreou became Prime Minister of Greece. After PASOK lost its majority in the Parliament, ND and PASOK joined the smaller Popular Orthodox Rally in a grand coalition, pledging their parliamentary support for a government of national unity headed by former European Central Bank vice-president Lucas Papademos.