PASOK was established in September 1974 following the fall of the Greek military regime and the restoration of democracy. Its founder was Andreas Papandreou, the son of the late Greek liberal leader George Papandreou. Its founding principle were "National Independence, Popular Sovereignty, Social Emancipation, Democratic Process."
At the November 1974 elections PASOK received 13.5% of the vote and won 15 seats, coming third behind the conservative New Democracy party of Konstantinos Karamanlis and the liberals of George Mavros. At the November 1977 elections, however, PASOK eclipsed the liberals, doubled its percentage of the vote and won 92 seats, becoming the official opposition.
In October 1981 PASOK won national elections with 48% of the vote, and capturing 173 seats and forming the first socialist government in the history of Greece. Although Papandreou had campaigned on opposition to Greek membership of NATO and the European Economic Community, he soon changed his mind and began renegotiation conditions for Greek entry to the EEC.
In 1985 the PASOK government revised the Greek Constitution to remove most powers from the President and to give wider authority to the Prime Minister and the elected Government. Many other sweeping social reforms were carried out. At the June 1985 elections PASOK 45% of the vote and won 161 seats. In June 1989, however, the PASOK vote fell to 40%, and the legislature was deadlocked. Another election in November produced the same result. After a prolonged political crisis a third election in April 1990 brought New Democracy back to power.
In opposition PASOK underwent a leadership crisis when Papandreou was prosecuted over his alleged involvement in the Bank of Crete scandal. He was eventually acquitted, and at the October 1993 elections he was able to exploit nationalist sentiment over the Macedonia and Cyprus issues to regain power. In 1995, however, Papandreou's health began to decline and PASOK was racked with leadership conflicts.
In January 1996 Papandreou was forced by ill-health to retire, and he was succeeded by Costas Simitis, the candidate of the modernising, pro-European wing of PASOK. Papandreou died in June, and became the subject of a posthumous cult among the PASOK faithful that now, with the decline of socialist ideology, provides its main focus of loyalty.
At the September 1996 election Simitis won a mandate in his own right, and in December Greece agreed to enter the Euro zone, burying the Greek nationalist ideology which under Papandreou had been PASOK's hallmark. In September 1997 Greece won the right to stage the 2004 Olympic Games. Simitis won another term in April 2000, winning 42.7% of the vote and 158 seats: a substantial achivement for a party which had been in power almost continuously for nearly 20 years.
On January 7 2004 Costas Simitis informed President Costis Stephanopoulos about the next national elections on March 7 2004, and announced his resignation as leader of PASOK. He suggested that PASOK leadership elections be held on February 8 2004. It is widely expected that the new PASOK president will be George Papandreou, son of Andreas Papandreou, who is expected to be the only nominee for the PASOK presidency.