As outgoing Defense Secretary Leon Panetta has said, the Pentagon's strategic shift is being driven by a recognition that America's security in the 21st century "will be linked to the security and prosperity of Asia more than any other region on earth."
The shift has implications for the services, too, particularly as America's decade-long wars in Iraq and Afghanistan come to an end. The Army and Marine Corps have been the go-to branches during this time. Now it is the Navy to which the Pentagon will be increasingly turning.
Currently, half of the Navy's ships are stationed in the Asia-Pacific region. This helps the US build relationships in the region, as well as reassure allies, says Adm. Jonathan Greenert, chief of naval operations.
Even as the threat of defense cuts loomed, resulting in calls to decrease the size of the Navy's aircraft-carrier fleet from 11 to 10, Secretary Panetta pushed back, citing the need for a Navy "able to penetrate enemy defenses."
The Pentagon is also putting money into developing a new "afloat forward staging base" in the Pacific, which can be used for everything from counter-piracy to mine clearing to Special Operations Forces missions.
Perhaps most public is the move of 250 US Marines to Darwin, Australia, last April, with the promise of as many as 2,500 at any given time in the years to come. Also, some 85,000 US troops are currently stationed in South Korea and Japan.