Malcolm Turnbull's approach to foreign policy will be far more nuanced than Tony Abbott's, and we can expect him to focus less on the Middle East and more on Asia, writes Hamish McDonald.

Same party, same generation, same university - but greatly different worldview: Australia's latest leadership switch brings a markedly different man into the prime minister's office.

Tony Abbott, 57, is deeply conservative. He's devoted to retaining the British monarch as Australia's head of state, opposes same-sex marriage, sceptical about climate change, and uncomfortable with the idea of global power and influence shifting from the English-speaking countries.

Malcolm Turnbull, 60, is reflective, giving wide-ranging speeches showing off deep research. Tech-savvy, he's connected with high-powered names in world capitals, and liberal in his social views. As a young lawyer he successfully beat an attempt by Britain's intelligence community to suppress the critical memoirs of MI5 officer Peter Wright. Later he led an unsuccessful campaign to replace the monarchy with an Australian republic. In his previous spell as opposition leader, he supported carbon pricing to inhibit global warming.

The September 14 vote in the Liberal Party caucus was not so much about policy: it was about winning elections.

But for the outside world, Turnbull will present a more sophisticated face than Abbott, less characterised by Anglophone nostalgia, and a much more nuanced approach to world affairs.

His stated reason for challenging the leadership was Abbott's persistent inability to articulate an economic vision for Australia and carry the population along with it. He stressed in one of a string of recent speeches:

Leaders must be decision makers, but they must also be, above all, explainers and advocates, unravelling complex issues in clear language that explains why things have to change and why the government cannot solve every problem.

Turnbull's own economic vision is an outward-looking one, urging Australians to meet globalised challenges rather than retreat from them. He told an Australia-China Business Council meeting in August:

We are in the most exciting, creative, disruptive time of human history. China is a big part of it - perhaps the biggest single part of it - and we need to be as mindful as the Chinese are of the need to rebalance our economy. And in this, the shift of the Chinese leadership to focus on the "qualitative" features of its economy, presents a huge opportunity for Australian businesses.

In a speech to the influential Australia-US Leadership Dialogue, a privately-run "second track" diplomatic forum in January, Turnbull singled out four trends that Australia needed to positioned for as "the rebooting of India, economic rebalancing in China, structural reform in Japan, and continued liberalisation of trade and investment".

In the debate about rising Chinese power and the US strategic role in Asia, Turnbull leans to the school urging accommodation between the two powers, as pushed by the Australian National University strategist Hugh White. Unlike Abbott, he would play down the growing US and Australian military-intelligence links with Japan, India, Singapore, Vietnam and other regional powers designed to counter Chinese maritime power.

He stresses the non-military aspects of Barack Obama's "pivot" or "rebalancing" to Asia, which includes the project Trans Pacific Partnership being negotiated between the US, Japan, Australia and nine other countries. Turnbull told the Australia-US forum:

Needless to say, the effectiveness of the TPP will be considerably enhanced by the inclusion of China, whose constructive participation in regional elements is a central element in its peaceful rise.

While acknowledging that the shift in Asia's strategic weighting would be different to Britain's amicable transfer of maritime dominance to the United States, Turnbull argued that a Chinese hegemony akin to the "Monroe Doctrine" of US sway in Latin America was the wrong analogy. He said:

The Western Pacific today on the other hand, apart from China, includes a nuclear power in Russia, the world's third largest economy in Japan, the world's fourth most populous nation in Indonesia not to speak of other powerful, rapidly developing powers. The construct of the Western Pacific as a lake in which there are only two players - the US and China - is just dead wrong.

China had over-reached itself with its recent spate of reclamations and sovereignty assertions in areas of the South and East China Seas, Turnbull said.

It has served to do no more than remind China's neighbours of the importance of a strong continuing American presence as a counter balance to China.

Despite this more active engagement with China and the region, Turnbull is unlikely to change the new Defence White Paper, expected to be published next month, which is reported to recommend investment in sea-power as part of the counterweight to China.

Turnbull has taken a markedly different tack on the crisis in Iraq and Syria than Abbott, who jumped in with military training and air support for Iraqi forces after the Islamic State group (also called Daesh) seized Mosul last year, and last week extended Australian air strikes into Syria against IS targets.

Abbott tightened domestic security surveillance and powers, warning that with dozens of young Australians joining IS in the Middle East and others urged by IS propaganda to carry out random attacks in Australia itself, the IS is "coming after us" and "coming ... for every person and every government".

In April, his Foreign Minister, Julie Bishop, made the startling assertion in a speech to the Sydney Institute, a conservative think-tank, that terrorism and the Islamic State presented the greatest threat to world order since the end of the Second World War, greater than the rise of communism and the Cold War, one that could "threaten the very existence of nation states".

In July, Turnbull took issue with this.

"Just as it is important not to underestimate, or be complacent about, the national security threat from Daesh, it is equally important not to overestimate that threat," he said. The IS was "not Hitler's Germany, Tojo's Japan or Stalin's Russia" and despite its aspirations to world domination, "we should be careful not to say or do things which can be seen to add credibility to those delusions".

With Bishop retained as Foreign Minister, Turnbull will have to bridge this difference. He is also likely to tone down Abbott's aggressive stance on national security. As he said in one recent speech:

Denouncing those who question the effectiveness of new national security measures as "friends of terrorists" is as stupid as describing those who advocate them as "proto-fascists".

If Turnbull pays more attention to Asia, he also sees a challenge in getting Washington to do the same.

"The scarcest resource is not military might or dollars," he said at the Australia-US meeting in January. "It is the time and attention of our leaders."

A version of this article appeared first in the Nikkei Asian Review.

Hamish McDonald is journalist-in-residence at the Australian National University's College of Asia & the Pacific.