The US Alliance
Australia now figures more prominently in US foreign policy than at any time since 1942-45, when Australian combat troops served under General Douglas MacArthur and scores of US air and naval bases and army camps were stationed Down Under.
Australia is one of five US security treaty allies in the Asia-Pacific (Japan, South Korea, Thailand and the Philippines are the other four), it will increasingly matter more to Washington. Unlike the other allies, Australia is not involved in any territorial disputes with its neighbours. The country is at the fulcrum between the Pacific and Indian oceans and has a long history of engagement in this region.
For all of these reasons, deeper engagement with Australia – including through increased presence of US military, surveillance, and intelligence assets on Australian soil; additional rotations of US Marines through Darwin; greater access to airstrips in northern Australia; and, potentially, a base near Perth for US nuclear submarines – is necessary to bolster the United States' rebalance to Asia. Indeed, for Washington, the US-Australian partnership has become a special relationship with few equivalents in the world. But few outside a small circle of policy elites seem to have noticed.
http://www.afr.com/news/world/north-america/how-the-us-and-australia-are-building-a-new-connection-20150304-13vi18