The 10th East Asia Summit this weekend promises to be one of the most interesting bits of summitry in some time. This, the last stop on Malcolm Turnbull’s five-nation tour which has included one-on-one meetings with the top three on Forbes' Most Powerful List, is also likely to prove the most challenging.

Rather than the more familiar topics of economic affairs, Mr Turnbull will have to negotiate an EAS geared toward discussions on the region's myriad security concerns. It's an opportunity for him to prove his foreign policy skills and show himself to be a handy all-rounder.

Mr Turnbull has a different worldview to his predecessor. There is a streak of realism that seems to drive a manual transmission, rather than automatic, in balancing relations between Australia's chief military ally and its biggest trade partner. And his consultative, business-centric approach is far more akin to that of his Asian counterparts than Tony Abbott's hawkishness.

Canberra has recently championed the 18-member EAS, which brings together the region's two key security guarantors and India, as one of the most important summits in the region's security architecture. As Australia’s top diplomat, Peter Vargese, described it in an address to the Lowy Institute earlier this year, 'From an Australian perspective, the EAS is the regional institution which has the highest priority and the most potential'. He added: 'A core objective of the EAS should be to nurture habits of consultation across the region'.

In the wake of the Paris (and Bangkok) attacks, counter-terrorism will top the agenda this weekend. The Southeast Asian boat people crisis, and irregular migration overall, are also likely to feature.

Indeed, with the onset of the sailing season across the Bay of Bengal and Europe's increasingly closed-border policy, the region may be set for a new, and potentially much bigger, wave of irregular maritime migration. Establishing regional frameworks to manage such flows would save lives and mitigate political fallout for national governments.

By far the thorniest issue to be discussed, however, will be the South China Sea and the US Navy's Freedom of Navigation Operations (FONOPs) last month. China's representative, Premier Li, will try to steer discussions toward a statement condemning the Paris attacks, similar to that agreed at APEC. China will also want to focus on improving counter-terrorism cooperation and the Regional Comprehensive Economic Partnership (RCEP). But a draft declaration from the EAS Chair which raises concerns over the South China Sea disputes and urges adherence to UNCLOS suggests the territorial disputes could be subject to perhaps their most intense discussions yet (they are also expected to feature in the ASEAN Chairman's statement).

This year, Canberra has spoken plainly on the South China Sea. Australian diplomats have emphasised that Australia's key interest in the region is to uphold the rules-based system. Further afield, Australia has also been vocal on Russia's flouting of the rules-based system in Ukraine. This weekend at the EAS, Russia and China, the two countries which have demonstrated 'strategic behaviour' (to use the language of Varghese) to test what they can get away with rather than adhering to rule-based norms, will be at the table. The 10th EAS may be viewed, to some extent, as a critical test of these behaviours. Australia is better placed for those discussions with an unblemished, shirtfront-free, Turnbull.

Michael Wesley noted this week that the US will be looking to leaders who have not been vocal against Beijing's (or Moscow’s) whatever-you-can-get-away-with behaviour to speak up. As Wesley wrote: 'The summits offer a chance for the US to put its allies and partners on the spot'. When Obama and Turnbull met earlier this week, they sang from the same songsheet, This weekend, Mr Turnbull could be pushed to go further.

Then again, as Ernie Bower has noted, the US is 'felling its oats' after a stellar few months. The TPP is signed, its bet on Aung San Suu Kyi in Myanmar (in which Hillary Clinton’s political future is heavily invested) has paid off, and Washington finally pulled the pin and launched FONOPs. Obama is coming into this EAS with a strong hand. That may give Australia more room to manoeuvre. Rather than having to stand behind the US, Mr Turnbull could take a bit of distance and possibly even act as a middle man in brokering agreement.

There are continued aspirations that the EAS, particularly in its 10th year, will live up to its potential and become the premier forum for the discussion of security issues in the region. If the EAS is bolstered, through either a series of reforms or by reaching significant agreement (such as on territorial disputes), it would be a big victory for both the embattled rules-based system and improved cooperation in the region.

It would also be a big win to mark on Mr Turnbull’s foreign policy record. The greatest pressures Mr Turnbull faces ahead of next year's election are domestic. However, a stronger EAS would put another shock absorber into the regional framework to address crises such as the South China Sea dispute, which always have the potential to upset an election campaign. Moreover, a more robust EAS, enabled by Canberra, would be a crucial support for the pivot of Australia's national psyche to Asia.

Photo courtesy of Facebook user Malcolm Turnbull.