The court also ordered that the two released men, Ahmet Turk and Sedat Yurttas, as well as two other Kurdish leaders freed last year, should face new trials under Article 8 of the anti-terrorism law for supporting the Kurdish nationalists.
"It's a disgrace, a purely political decision," said Mahmut Alinak, released last year and the only one to regain his parliamentary seat. "My original conviction was based on fabrications by policemen and informers. It's just some make-up to look good for Europe."
The European Parliament has demanded the release of all six former MPs as a condition for ratifying a key customs union agreement with its Muslim neighbour.
Conservative Turks have resisted, saying that most of the MPs were convicted for links with rebels of the Kurdistan Workers' Party (PKK).
"They should be executed," said Nusret Demiral, the outgoing chief prosecutor of the State Security Court system.
The Europeans have also demanded reform of Article 8, which sets out jail terms of two to five years and heavy fines for "propaganda against the indivisible unity of Turkey". The government's revised version of Article 8 passed a parliamentary commission on Wednesday. It will empower the state to close radio and television stations from one to 15 days as a punishment, but is otherwise less onerous. Penalties are to be reduced to one to three years in prison, "propaganda" is less broadly defined and sentences may be suspended.
The legislation will also be retroactive. If implemented, several of 170 writers, intellectuals and Kurdish nationalist militants may be freed from jail and many of the trials of another 5,500 people may be dropped.
"This is all there is going to be. With this, the European Parliament can make its decision in December. At this rate, Turkey will be lucky to get customs union," said a European diplomat in Ankara.
Another said it was a step forward, if limited, and that the Commission in Brussels still supported the free-trade pact.
The Turkish establishment, however, has only half an eye on the customs- union bid. Its attention is consumed by a political crisis out of which the conservative Prime Minister, Tansu Ciller, is supposed to form a coalition government with the Social Democrats by 5 November or fall. Parliament yesterday discussed an attempt to set an early election date of 24 December, a date none of the parliamentarians really wants.
Any date before the spring is also probably unachievable, given the millions of names in Turkey and abroad that must be added to electoral rolls, and therefore is likely to be thrown out by the Constitutional Court.
"There's no flour and sugar, yet you want us to make halva," said an exasperated Nihat Yavuz, head of the Supreme Election Board.
Mrs Ciller did have some good news yesterday as she finally settled a five-week strike by public-sector workers. She will now have to find the money to pay for that and an equally generous deal with 1.5 million civil servants, at the same time as sticking to an IMF-ordered programme to cure annual inflation now exceeding 90 per cent.
But that little problem, like most things in today's turbulent Turkey, is something everyone seems happy to leave to tomorrow.