Australian officials used to fret about the so-called 'arc of instability' of Melanesian nations in our neighbourhood, with particular concern about regular votes of no confidence in our former colony, Papua New Guinea.

But the sudden mid-term overthrow of Australia's Prime Minister Tony Abbott and his replacement by Malcolm Turnbull has people in PNG wondering which of the two countries now has the more settled political atmosphere.

In fact, since 2002, while Australia has chopped and changed prime ministers at such a remarkable rate – from John Howard to Kevin Rudd to Julia Gillard to Rudd again then to Abbott and now to Turnbull – Papua New Guinea has had only two – Sir Michael Somare and Peter O'Neill.

That would seem to indicate pretty impressive political stability: two prime ministers in 13 years compared with Australia's six.

The fact that Abbott was in Port Moresby (for the Pacific Islands Forum) only a week before his downfall led one PNG wag on social media to suggest that Australian Prime Ministers were courting their own demise by visiting PNG. He went through the history: how Gough Whitlam was removed just months after being in Port Moresby in September 1975 for PNG's Independence; and how both Gillard and Rudd had both lost the prime ministership not long after each returned from a visit.

Of course, PNG has had its fair share of constitutional crises. The transition from Somare to O'Neill led to one when the PNG Supreme Court ruled that Somare had not been replaced by O'Neill in the constitutionally correct way. This was despite the fact that when O'Neill took over, Somare was incapable of carrying out his duties because he was in hospital in Singapore and his family had announced his resignation some months earlier on the grounds of health. 

But Somare recovered, returned to PNG and, following the Supreme Court ruling, tried to assume control again. So Papua New Guinea had, for a brief time, two prime ministers, two police commissioners and two commanders of the Defence Force. But, despite the potential for mayhem, none eventuated. 

O'Neill continued governing, an election was due and was held (in 2012) and he secured the numbers to form a new government. PNG politicians are nothing if not pragmatic and although the two of them had been virtually at war for months, Somare, initially at least, threw his members' support behind O'Neill.

It is worth examining how this more stable political environment has come about if we Australians are to understand how democracy in PNG works. 

Not the least of the contributing factors were constitutional reforms introduced during the term of Sir Mekere Morauta from 1999 to 2002. PNG has elections every five years but up until 2002 not a single government had survived a full term. Mid-term changes of government through votes of no confidence had become the norm. 

Sir Mekere told me in an interview a few months after he became prime minister that the 'underlying uncertainty' regarding political loyalty in PNG made governing difficult. 'No one is really sure who is going to abandon me in the next vote,' he said.

Morauta set about trying to stabilise PNG's political system. 'One of the achievements,' Morauta says, 'was the Organic Law on the Integrity of Political Parties and Candidates.' 

The Registrar of the body set up under that Organic Law, the Integrity of Political Parties and Candidates Commission, Alphonse Gelu, recalls Morauta named his reform program 'Date With Destiny'. 'That title was right at that time because he instituted a lot of changes not only with political reform but also in the area of financial regulation such as making the Central Bank more independent,' Gelu says. 

He continued, 'There were two things as part of that political reform that he instituted. The first was the passing of the Organic Law on the Integrity of Political Parties and Candidates and the second one was the change in the voting system from first-past-the-post to a limited preferential system . . .  Those measures helped to create more certainty in PNG politics. Prior to that things were just all over the place.' 

Prime Minister Peter O'Neill has proved himself to be a master tactician in this new political landscape in PNG. He acknowledges that the Integrity of Political Parties legislation 'played a key role' in reducing political instability. 

'The party system is still weak,' O'Neill says, 'but it is maturing.' His Peoples National Congress Party outperformed all others in the 2012 elections and since then he has gone from strength to strength. 

The limited preferential voting system that came into force in the 2007 elections is another contributing factor to greater political stability. Under the first-past-the-post system previously in place some members were elected with as little as 7% of the vote. This is not so surprising if you consider that the average electorate covers half a dozen or more language groups and the number of candidates could top 50. 

The success of limited preferential voting in ensuring that those elected actually have significant community support beyond their own tribal group is clear from the 2012 election results. About two-thirds of the MPs elected never topped the poll on the first count but benefited from being listed as the second or third choice for voters whose number one pick dropped out.

PNG still has a multitude of challenges to confront but chopping and changing prime ministers mid-term now seems to be more a feature of Australian politics than PNG's.

Photo courtesy of Flickr user Tony Abbott.