Both will now be scrambling to find some way to circumvent the decision and continue a policy that seeks to deter boat arrivals by subjecting those who have already come to ongoing punishment, harm and misery. Prime Minister Malcolm Turnbull Credit:Alex Ellinghausen One way around the decision is for the PNG parliament to pass another constitutional amendment or other legislation to make the detention lawful. This is problematic on two fronts: whether Prime Minister Peter O'Neill has the appetite to push it; and whether it would pass. Another would be to declare the detention centre an "open facility", as happened in Nauru, but this would be a much greater challenge on Manus, where resentments remain strong from the 2014 riots that saw Reza Barati killed and scores of asylum seekers injured. It would also be more challenging because the detention centre is so far from the island's only town and because more than 300 of the asylum seekers have not had their claims processed.

"They won't be coming to Australia", is the predictable, knee-jerk response from Immigration Minister Peter Dutton, but they should be brought here, even if some are ultimately resettled elsewhere. Rather than try to prop up a punitive, immoral and now illegal policy, the focus should be on developing a humane alternative based on regional cooperation with countries including Indonesia, Malaysia and Thailand. Such a policy could see an agreement for returning boat arrivals to transit countries for processing, provided their human rights were respected, and the refugees on Manus and Nauru resettled in Australia, New Zealand and other developed countries like the US and Canada. Releasing about 900 men into the Manus community is impossible on logistical and practical grounds, including the hostility of locals to any such proposition. The same goes for relocating them to PNG's major cities, Port Moresby and Lae. Transporting them to Nauru is not a viable option for similar reasons: the tiny island and its already strained infrastructure could not cope.

If it was not so tragic, it might be funny The unsustainability of the whole exercise is demonstrated by the statistics. Despite the promise that those found to be refugees would be resettled in the first half of 2014, only eight refugees out of more than 1000 are no longer institutionalised. Three found life in Lae so threatening and unbearable that they returned to Manus Island and attempted to find refuge in the transit centre set up at massive cost to facilitate their release. As Fairfax Media reported over the weekend, one spent the night in the Lorengau police lock-up after attempting to scale the transit centre fence when he was refused entry. If it was not so tragic, it might be funny. This leads to a third possible response from the PNG government: to tell Australia it is no longer bound by the agreement and to find another way to solve its problem - to declare enough is enough.