The BBC's Jill McGivering looks at prospects for peace in Mindanao, where fighting between Philippine troops and separatist rebels is causing a humanitarian crisis.
MILF separatists have been fighting the Philippine government for decades
In mid-2008, it looked as if there was at last - after decades of fighting - a chance for Mindanao to find lasting peace.
Eight years of negotiations between the Philippine government and the separatist group, the Moro Islamic Liberation Front, or MILF, had resulted in a framework agreement.
In early August, representatives from both sides gathered in the Malaysian capital, Kuala Lumpur, to sign the landmark deal. But the signing never took place.
The document faced fierce opposition at the 11th hour, including from some Christian leaders who challenged its legitimacy.
They complained that the government had failed to discuss the deal adequately with Christian communities in Mindanao - who form a majority on the island - and with the island's indigenous people, despite the fact both communities would be directly affected.
The final collapse of the long-awaited agreement came when the Supreme Court in Manila declared it unconstitutional.
The deal had been provisional but paved the way for an expanded autonomous Muslim region with a high degree of self-governance.
The Red Cross distributes food to displaced people in the Philippines
Emmanuel Pinol, the vice-governor of North Cotabato, which would have become part of the new expanded region, was one of its most vocal critics.
He told the BBC that, in his opinion, the whole approach was flawed.
The document made provision for a separate police force, local security force and a separate judicial system, he said.
It would divide many people in Mindanao from the rest of the Philippines but the real answer to the long-standing sense of grievance felt by many Moro people, he went on, lay not in a treaty but in grassroots development.
The collapse of the deal has left a political vacuum and a great deal of uncertainty about the future.
Of the 19 commanders associated with the MILF, three are now locked in day-to-day fighting with the Philippine army.
I don't see any prospect of signing a peace deal under the Arroyo administration
MILF chief negotiator
According to a Philippine army estimate, these three commanders have a total force of about 2,000 fighters.
Some MILF leaders who advocated support for the ceasefire and the peace process now feel betrayed.
I went to the MILF jungle headquarters to meet their chief negotiator, Mohagher Iqbal.
He is now in his 60s, a well-educated and softly-spoken man who was a rebel fighter in his youth. Now, he told me, he had lost faith in the government's sincerity.
"I feel frustrated," he said. "At the final moment, the government decided not to sign. This is treachery of the first order."
The prospects for further talks seem bleak. Both sides say that in theory they are ready to resume negotiations.
But the fact the Supreme Court declared the deal unconstitutional casts a shadow over future agreements which are founded on similar principles.
The situation is further complicated by the fact that the current President, Gloria Arroyo, now has a limited term of office. Her mandate expires in 2010.
"I don't see any prospect," Mr Iqbal told me, "of signing a peace deal under the Arroyo administration."
There are some international efforts to broker fresh talks and get the peace process back on track.
But in the short term, it seems unlikely that the MILF leadership will be able to convince commanders who are now fighting to stop.
And until the violence ends, the tens of thousands of families who fled their villages, and are now trying to survive without adequate food or shelter, will not be able to go home.
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