In World War II, this country served the allied cause as a giant aircraft carrier and port, providing planes, men and materiel to deploy throughout the Pacific. Allied aircraft flew from the northeastern town of Cairns during the Battle of the Coral Sea — known by some as the “battle that saved Australia.”
The Battle of Milne Bay on the eastern tip of New Guinea, little known to Americans, marked the first time allied troops turned back what had been the unstoppable Japanese. Australians fought that battle, aided by allied aircraft flying from an airstrip inland of the port of Townsville, which played crucial roles in virtually every battle of the Pacific.
Today, the strategic situation is very different. The greatest threats to peace in the region are North Korea and an increasingly assertive China. Indonesia has replaced Japan as the central threat faced by the Australia, although relations between the two states have improved considerably over the last two decades. Defense policymakers still consider the Aussie military’s ability to defeat Indonesia a primary benchmark.
What does all this translate into? Defend Australia from the north (hence the carefully circumscribed agreement to allow US Marines to operate from Darwin but not to be based there) and ensure Australian submarines can avoid its enormous shoal waters and deploy undetected from the deep water ports in the south to help protect the country.
That has been the essential model for a long time but some basic strategic facts have recently changed.