On Wednesday, the United States and Japan released an interim report on updating their defense cooperation guidelines, of which a few notable yet worrying alterations should be noticed by Japan's Asian neighbors especially China and the Republic of Korea.

On Wednesday, the United States and Japan released an interim report on updating their defense cooperation guidelines. [File photo]

For starters, Japan's decision to lift a ban on collective self-defense in July, will be "appropriately reflected" in the updated guidelines. Vague as the wording seems, however, the report elaborates under what circumstances Japan will be allowed to use military force to assist its allies under attack and how.

Moreover, both Washington and Tokyo insist on expanding the scope of cooperation between their militaries by removing the existing geographical limits in the future. In specific, "seamless cooperation" between the two, including marine safety, intelligence gathering, and missile defense, shall be launched "from peacetime to contingencies", according to the report.

The report, which aims to revise the mutual defense guidelines for the first time since 1997, therefore sheds a new light on the policy moves of the US-Japan alliance in the years to come. The revised version, which allows Japan to wield force to help an embattled ally and enhance its military cooperation with the US, indicates that the ban on Japan's collective self-defense is being practically lifted within the US-Japan alliance.

Legal restrictions hindering such an act are still valid in Japan. Yet, they are likely to be removed by the reinterpretation and revision of the law, just as the Abe administration did to the country's "Peace Constitution", overhauling Japan's exclusively defense-orientated post-war security policy.

It is also foreseeable that both countries will expand the scope of their military cooperation globally and specifically. Issued in 1997, the existing US-Japan defense guidelines focused more on the regional defense deployment in Japan and its neighborhood.