Q: Which neighbour is more different to Australia—Indonesia or Papua New Guinea?

A: Impossible to say.

As neighbours forever, Australia, PNG and Indonesia constitute an extraordinary triangle. The contrasts and clashes abound. Each neighbour is so unique, defining degrees of difference is impossible. That impossibility informs much of importance.

For Australia, Indonesia and PNG are the two key regional relationships. Indonesia sets the tone ^[1] and temperature ^[2] of what Australia can do in Southeast Asia. PNG is the most important country in the South Pacific ^[3] for Australia (along with New Zealand), and it frames our thinking about the South Pacific.

Oz defenceniks/diplomats enter the triangle hesitantly. The bulging bilateral baskets dominate. When Australia speaks of Indonesia, it rarely links to PNG. And when Canberra cogitates on PNG—less than it should—it doesn’t travel on to the Indonesian dimension. The two bilateral relationships are so big, it’s tempting not to complicate things further with the triangle.

For vexed Oz policymakers throughout most of the 20th century, a wonderful element of today’s triangle would astonish—all three are democracies. Even sharing such a basic value, though, can be another point of difference; the vibrant, muscular election going on in PNG is proof anew that democracy has many colours.

I’ve been contemplating the triangle because of a marvellous new book by a former Australian diplomat, Bruce Hunt: Australia’s northern shield? PNG and the defence of Australia since 1880 ^[4].

Hunt offers the best sort of history—digging across familiar ground but turning up lots of new nuggets. The familiar bit is the way Australia’s leaders have consistently seen PNG as a shield (the question mark in the book title is swept away by lots of evidence).

Hunt starts with an 1883 quote from Queensland’s Premier, T.J. McIlwraith: ‘The establishment of a foreign power in the neighbourhood of Australia would be injurious to … Australia’s interests.’ Then a matching sentence from the 2016 Defence White Paper ^[5]: ‘Australia cannot be secure if our immediate neighbourhood, including PNG, became the source of threat to Australia.’

Across the 130 years between those twin statements, Hunt traces Australia’s PNG obsession. In 1901, Billy Hughes set the northern shield template for PNG, stating: ‘We must take it.’

Hughes’ argument that Australia must have PNG to deny a hostile power a base for invading the continent set a bipartisan template embraced by later leaders as diverse as Evatt and Menzies.

‘Fear of Australia’s Asian neighbours,’ Hunt writes, ‘dominated Australia’s consideration of the value of PNG.’ At the start of the 20th century, the newly minted White Australia wanted PNG for its territory, not its people.

Hunt hits narrative gold with Indonesia’s independence after World War II, as the triangle took shape. He devotes six chapters to ‘the spectre of Indonesia’ haunting the PNG policy of Australia’s Coalition governments in the 1950s and ’60s.

The story is told through the two great differences—over Dutch West New Guinea and Sukarno’s Confrontation. Those two ‘critical episodes’ were ‘considered by the Menzies and Holt Cabinets on over 60 occasions in specific detail or in the context of analysing Australia’s strategic environment. On nearly each occasion ministers linked Indonesian actions to possible threats to PNG’.

In the early stages, the Menzies government was determined Indonesia must never take West New Guinea from the Dutch, and equally resolved to go to war if Indonesia attempted to unsettle PNG by infiltration, subversion or attack.

The Dutch, however, got little backing from the US or Britain; Australia’s determination withered and belligerence softened. One of Cabinet’s key hawks, the Country Party leader, Jack McEwen, saw the broader danger of military conflict with Indonesia over West New Guinea, warning ‘a fracas over this is a fracas with Asia’.

By the time Gough Whitlam’s whirlwind arrived in 1972, Australia was less worried about threats from Suharto’s Indonesia; the new fear was what would become of independent PNG, rushed to birth in 1975.

Australia could no longer own its northern shield. Uncertainties about PNG’S future coloured the terms of the security guarantee. In stepping back from its colonial role, Hunt writes, the Whitlam government didn’t want to make ‘an open-ended commitment to defend an independent PNG’. By 1986, Australia’s Defence Minister, Kim Beazley, told Indonesia’s military chief, Benny Murdani, that Australia would certainly go to war for PNG ^[6], ‘but we wouldn’t tell them that!’

Hunt concludes that PNG ‘is no longer seen as a shield or a bulwark to protect Australia from invasion’. Modern defenceniks might demur—old, deep habits die hard. Yet Hunt reflects the reality that if there’s to be any shield, it’ll be based on the triangle—with, not against, Indonesia.

In telling that story, Hunt makes masterful use of the notebooks detailing Cabinet debates ^[7], released to the public after 50 years. Cabinet is the black box at Canberra’s heart: facts leak but the secret shroud prevails. Hunt’s account of the triangular defence and security debates, stretching over decades, is proof that Cabinet delivers Australia a flexible whole-of-government system, as able to act swiftly as to chew away at big challenges for years.

The triangle now has a twin. Australia gives Timor-Leste a de facto defence guarantee—we signed that in 1999 and have been acting on it since. A second guarantee to a second country with a land border with Indonesia. Like the PNG triangle, the Timor triangle carries much history as well as plenty of hope.