Secretary of Defense Chuck Hagel arrives in Sydney, 11 August 2014. (Department of Defence.)

US Secretary of Defense Chuck Hagel touched down in Sydney today for the annual AUSMIN meetings between Australian and US foreign policy and defence leaders, which start tomorrow. There will be no shortage of crises for the leaders to discuss, from coup rumours in Baghdad to the ongoing conflicts in Gaza and Ukraine. Leaders will also sign off on existing force posture agreements that permit the rotational presence of US Marines and the US Air Force in northern Australia.

But the long term issue of most importance to the alliance which needs to be discussed this year is the future force posture of the US Navy in Australia.

At the 2012 AUSMIN in Perth, then Australian Defence Minister Stephen Smith said that the growing strategic importance of the Indian Ocean was leading the US Navy to shift its attention to the waters off Australia's northwest coast. That AUSMIN meeting committed a joint working group of Australian and US officials to investigate options for the additional presence of US Navy vessels on Australia's west coast. A formal study didn't begin until December 2013, and the group will report its finding to the leaders over the next few days with a view to forging a way forward to new naval force posture arrangements.

In a sense, the presence of the US Navy in Western Australia is nothing new. US Navy Expeditionary Strike and Carrier Groups have been visiting the port at HMAS Stirling for decades. But the shift in economic power within Asia, the modernisation of the Chinese and Indian militaries, and the growing importance of energy transit routes through the Malacca Straits is leading US strategic planners to think more about the potential for crisis in Southeast Asia.

Two recent studies from the Center for Strategic and International Studies and RAND Corporation, both supporting the ongoing US global force posture review, concern themselves with the need to move large numbers of US Marine Corps troops into Southeast Asia. Both endorse the expansion of the Marine Rotational Force-Darwin into a full-size Marine Air/Ground Task Force and then consider further naval and maritime intelligence, surveillance, and reconnaissance initiatives which might be appropriate. The CSIS report considers the presence of a US Carrier Group in Western Australia, but dismisses it as too expensive, given the near US$6 billion cost of facilities upgrades. 

Both reports mention the possibility of home-porting a US nuclear submarine at HMAS Stirling. This option is attractive, given HMAS Stirling hosts one of the few Mark 48 Torpedo Maintenance Facilities in the southern hemisphere and so can recondition and resupply submarine munitions. The Royal Australian Navy also has readily accessible underwater exercise areas and submarine rescue training facilities at HMAS Stirling.

However, the most likely force posture option under discussion is for the future rotational presence of a US Amphibious Ready Group (ARG) at HMAS Stirling. The Marines based in Darwin will need some kind of sea-lift if they are to operate in Southeast Asia, and it makes more sense to base this in Western Australia than in other nearby locations. The US Chief of Naval Operations last year flagged his intent to raise another ARG in the lower Pacific region. Local political considerations in both the US and Australia would make home-porting the ARG in Perth difficult, but a rotational presence would make sense.

This would require some additional berthing infrastructure at HMAS Stirling, as well as the possible construction of additional ramp space at nearby airfields, but it is far less costly than other options. For the US, this would preposition assets closer to potential trouble spots, diversify basing (particularly outside of the range of potential adversary missile systems), and allow an enhanced and more regular Indian Ocean and Southeast Asian presence, using fewer vessels than if a forward presence wasn't available.

Australian leaders will need to make more of a case for why this option needs to be explored and how the alliance is evolving. Currently, questions regarding force posture are met with relatively simple endorsements of the strength and shared vision of the US alliance. That cedes much of the ground in the discussion to strident critics such as former Prime Minister Malcolm Fraser, who argues that Australia should withdraw from the alliance entirely. At this AUSMIN, it is not only important to work through the options privately, but to discuss how to make a detailed public case for why such steps are beneficial to both countries.