With President Donald Trump pulling the United States out of the Trans-Pacific Partnership trade deal and abandoning predecessor Barack Obama's policy of a strategic rebalance, or "pivot," to Asia, Southeast Asian scholars have urged Japan to play a greater role in regional security.

They suggest that Japan, for example, should provide more patrol vessels to the Philippines, Vietnam and other coastal states around the South China Sea to boost surveillance and law-enforcement capabilities at a time when China is becoming increasingly assertive about its territorial claims in the contested waterway.

"Japan's role is very important" because Trump's comprehensive Asia policy is not yet in sight and Beijing is advancing militarization of its outposts in disputed areas in the South China Sea, said Tran Truong Thuy, a deputy director of the Bien Dong Maritime Institute at the Diplomatic Academy of Vietnam.