Toroama had also alluded to Australia’s collaboration with PNG during the Bougainville civil war of the 1990s.

The association between the Australian military and what is now the PNG Defence Force goes back to World War II and obviously included the period of the civil war.

However, so far as I am aware, Australia's military played very little if any part in the planning or implementation of any PNGDF operations within Bougainville.

This would have made no sense at all to the military or political leadership of that time, and it does not make any sense now.

If, as may well occur, Bougainville unilaterally secedes from PNG in 2027, I would be very confident that neither the Australian, New Zealand, the USA nor any Pacific Islands government would be willing to support military action against it.

An independent Bougainville will necessarily be an impoverished mini-state. It lacks the economic foundation to be much more than a subsistence-based economy, although there may be wealth creation opportunities around mining and tourism.

The PNG government is highly unlikely to agree to transfer wealth to an independent Bougainville if for no other reason than to serve as a warning to others within PNG who may harbour secessionist ideas.

Quite what will happen is an open question. The world's major powers might be willing to direct resources to Bougainville in return for such things as the right to build naval and air force facilities on the island.

The USA has a well-established track record for doing this and China might wish to do so as well.

I mention these things not because I think they will necessarily occur but to illustrate just how fraught this issue has become well beyond the borders of PNG.

It is, as I have written before, a 'wicked problem' for which there is not an obviously 'right' answer.

If I was asked to nominate a plausible solution to the dilemma confronting PNG, I think I would suggest that it adopt a federalised constitutional structure similar to that of the USA, Australia or Canada.

Federation confers a great deal of autonomy upon newly created state or provincial governments but within the constituted structure of a nation.

This might be enough to convince Bougainville to remain a part of a 'United States of Melanesia' rather than continue to go its own way.

Of course, this is a huge change to contemplate but it is not undoable if there is the will to embrace radical constitutional reform.

Also I have little doubt that it would be tricky to manage, requiring a great deal of the supposedly inbuilt Melanesian capacity for negotiation, compromise and consensus building.

In some ways it would reflect a return to the pre-colonial past, in which Papua New Guineans lived within loosely understood tribal boundaries, subject to their own laws and rules about the production and distribution of resources.

A big risk with a federal system, apart from disputes about resource distribution, include atomisation, where so many tiny 'statelets' are created including some that are not viable entities in their own right.

If I can imagine such a future for PNG surely it will have dawned upon that country’s leaders that the drastic change to a federal structure may be the price of maintaining national cohesion in the face of secessionist pressures in Bougainville and other provinces.

Determining the fate of Bougainville will become a litmus test for the future of a united PNG.

Hence Richard Marles very cautious – but still incendiary - statement about supporting the PNG parliament as it works through the process of determining whether it will approve Bougainvillean independence or not.