US presidents arriving in Australia always cause the locals to hear military echoes. Driving in from Canberra airport, Obama can glance to his right and see a striking symbol of the unique military relationship Australia has with America.

At the very centre of the Defence Department complex stands a soaring 78-metre column, topped by an eagle. It is the Australia-American memorial, erected with money contributed by ordinary Australians as an expression of 'grateful remembrance of the vital help given by the United States during the war in the Pacific'.

Thus, one of the three big symbols that define Australia's national capital is actually a tribute to the US (the other two are the flag above Parliament House and the Captain Cook water-jet in the lake). Add to that list a building which also rates as a symbol — the Australian War Memorial. The American memorial and the War Memorial, bordering opposite ends of the same suburb, speak to a lot of common history (which is one reason Obama will go to the War Memorial).

These monuments framing Canberra reflect the deep Australian attachment to the alliance, which over its life has had a remarkable potency in the conduct of Australian politics as well as in the definition of Australia's military options.

As the column on the 60th birthday of ANZUS mused, that potency explains much about why Australia keeps volunteering for US wars — the blood price that is regularly paid. The payment is a product of current opinion polls and the continuing tithe set by history. Those who contributed £100,000 to have the American memorial built in Canberra in 1952 were the people who had just lived through Australia's great moment of truth in the 20th century.

The memorial marks the national trauma and existential struggle involved in the fall of Singapore, the attacks on Darwin (the Japanese sent as many planes as they did at Pearl Harbor), the battle of the Coral Sea and the fight for New Guinea. As Coral Bell has observed, this patch of history has 'haunted Australian strategic inquiry every since'.

Coral also produced one of the great books on the alliance, certainly the one with the sharpest title: Dependent Ally. The sense of dependence is not quite as deep as it was 27 years ago when Coral brought out her first edition, but the label is still apt. Kim Beazley, the former Labor leader now ambassador to Washington, has made the argument that the balance of advantage in the US-Australia alliance 'has shifted to the Americans'.

It is a tough case to win. But Obama's announcement of increased US use of Australian military facilities will speak to an easier argument about mutual interests and some mutual dependence in specific areas. Thus, the politics of the Obama announcement will be overwhelmingly pro-American. Labor and the Coalition will line up together to applaud an increased US military presence on Australian soil. The Greens will oppose. The divide roughly reflects the pro-US state of the Lowy polls.

One way to understand why the alliance is so deeply entrenched is to go out the front door of Parliament House and walk on to the right of the forecourt to the point where you can look along the length of Kings Avenue. At the far end of the avenue stands a tall symbol that is also a sentinel of the Australia-American relationship.

Photo by Flickr user KLW NFC.