The study by the United States Study Center, at the University of Sydney, in Australia, warned that America's defense strategy in the Indo-Pacific region "is in the throes of an unprecedented crisis" and could struggle to defend its allies against China.
That means Australia, Japan and other US partners need to build up and refocus their forces in the region, and consider increased cooperation with the US, to ensure their security, the study claimed.
The report, for example, suggested that Australia increase its production of conventionally powered submarines, which are ideal for operations close to coastlines or in areas like the South China Sea. It also encouraged "collective defense" through software that enables communications between allies.
The strain that conflicts in Afghanistan, Iraq and Syria have placed on the US military's budget, equipment and operations had "ill-prepared" Washington "for great power competition in the Indo-Pacific," it said.