Donald Macintyre: Before any hope of progress, this truce must hold

If the still fragile Gaza ceasefire holds, then logic, a commodity all too scarce in the Middle East, will have prevailed for once.

The Israeli military operation began in June in response to the seizure by militants of Corporal Gilad Shalit and the killing of two of his comrades. But the Israeli authorities had long realised that negotiations - at least as much as military pressure - would be needed to secure his release.

Equally, it had become apparent that military means alone could not end the firing of Qassam rockets - the second objective of the operation. This point had been made by the Israel Defence Forces' chief of staff, Dan Halutz, at a recent cabinet meeting.

From the point of view of Palestinian militants, Qassam rocket fire has brought fear and misery to the Israeli border town of Sderot and killed two Israeli civilians there in the past month. But easily the worst consequences, because of Israeli counter-measures, have been for the population of Gaza as a whole, as some Palestinians had begun to state openly long before the Israeli shelling attack which killed 18 members of the same civilian family in Beit Hanoun three weeks ago. Around 400 Palestinian lives have been taken since June, including those of at least a substantial minority of civilians, women and children among them. That it was logical did not, however, make the ceasefire inevitable, any more than it will make it easy to maintain. For Ehud Olmert and Mahmoud Abbas, two leaders widely depicted as badly weakened, it is something of an achievement.

Mr Olmert had already resisted the vainglorious calls for a full-scale, in human life incalculably costly, and probably futile, repeat of the 2002 Operation Defensive Shield in Gaza. By accepting Mr Abbas's proposals for a ceasefire, he has now risked afresh the wrath of a right wing emboldened by the failures of the war in Lebanon this summer and waiting menacingly for any Palestinian breach, however minor and renegade, of the ceasefire. Indeed this opposition could in time be led by his own Deputy Prime Minister, Avigdor Lieberman. He reportedly told a recent meeting of the security cabinet that Israel should adopt the same approach to Gaza as the Russians had to Chechnya, and this month proposed an international campaign to sideline Mr Abbas as "irrelevant".

The Palestinian President, for all the widely perceived erosion of his personal authority, has managed to deliver most of the armed factions once again, as he did in January 2005 soon after taking office.

It is still far too early to be optimistic on a wider front, significant as the ceasefire is. In theory it could pave the way for a prisoner exchange and the early release of Cpl Shalit; a "unity" Palestinian government which could start attracting back desperately needed Israeli and international funds. This, in turn, could help the prospects for a substantive meeting, accelerated perhaps by the presence of the US President and his Secretary of State in the region later this week, between Mr Abbas and an Israeli Prime Minister who has apparently shed his belief in unilateralism in the wake of the Lebanon war.

To assume that all this - let alone a real peace process that will open "final status" talks on a two-state solution - will follow smoothly would be a triumph of hope over experience. It is true that the highly tentative prospect of a shift of US Middle East policy after the former secretary of state James Baker delivers his famous recommendations on Iraq could, if realised, help to make some progress possible.

But first and most mundanely, the ceasefire itself has to hold amid continuing confusion over whether Islamic Jihad and at least one of the Fatah-linked factions have any intention of adhering to it. And as Mr Abbas knows from bitter experience of negotiating ceasefires that were undermined by attacks from both sides since he was Prime Minister under Yasser Arafat in 2003, it may not.

The best guess that can be made for now is that a majority of Gaza's 1.3 million people, not to mention of the increasingly beleaguered 25,000 residents of Sderot, will be hoping fervently that it does.