For Australians, August 15 is the date World War II finally ended. In years to come, it may also mark the day one of Asia's longest-running wars ended.
A peace treaty signed yesterday by representatives of the Indonesian Government and the separatist Free Aceh Movement (GAM) is hugely significant, both for Indonesia and its reformist President, Susilo Bambang Yudhoyono, and for relations with Australia.
Since Dutch colonial rule, Aceh has been locked in separatist conflicts, which resumed less than a decade after Indonesia's 1945 declaration of independence. The modern phase of the conflict, in which 15,000 people have died, began with the founding of GAM in 1976. In May 2003, Indonesia sealed off Aceh.
More than 3000 people were killed and rights atrocities multiplied in a brutal "secret war" that offered little hope of a peaceful resolution.
Then the Boxing Day tsunami hit with catastrophic force and Aceh bore the brunt of it, losing more than 130,000 people. The calamity transformed the political atmosphere. The scale of human loss and of the reconstruction task brought both sides to their senses.
Aceh was opened to foreign troops and aid workers – despite the Indonesian military's obvious reluctance.
Peace talks also began. The tsunami was a catalyst for this and for Australia's huge investment in its relationship with Indonesia through a $1 billion aid and reconstruction program. Australia had an obvious interest in peace talks and academic Damien Kingsbury was involved directly as an adviser to GAM.
As he cautions, it remains to be seen whether the treaty holds. The presence in Aceh of militia backed by the Indonesian military (TNI) arouses fears that the province could be in for the same horrific destabilisation East Timor suffered in 1999.
Corrupt business worth an estimated $400 million gives the TNI an interest in running Aceh; the Government's challenge is to run the military. Dr Yudhoyono was the first president directly elected by Indonesians, who voted for him because he promised real reform that would free them from the grip of the corrupt elite that survived the collapse of the Soeharto regime in 1998.
His promise of a democratic Indonesia, governed by the rule of law, is incompatible with the old approach to subjugating Aceh (or any other provinces).
Aceh is a test of the democratic credentials of Indonesia and its President. Dr Yudhoyono deserves Australia's support, having done much to help the countries' relationship recover from the rift over East Timor.
Human rights abuses are still an obstacle to the full restoration of ties with the US and Australia, despite the mutual interest in security co-operation, so they must hope the TNI bows to the authority of its elected government.
It is hugely important not only for Aceh but for Indonesian democracy and prosperity that the peace holds and reconstruction of the oil-and-gas-rich province proceeds.
Indonesia lacks the money and means to go it alone, but it should not be seen simply as a charity case – for one thing, Jakarta is a key advocate for Australian involvement in the region. Australia, in return, is in the happy position of being able to draw on its postwar prosperity to help its ally seize the opportunities that peace and democracy create.