Shinzo Abe's decision to accept advice from a panel of experts that Japan could participate in collective self-defence by fighting to protect allied countries if they come under attack is a major shift in his country's foreign and defence policy. Article 9 of Japan's constitution renounces war, a constraint Mr Abe resents but is politically unable to change. Instead this reinterpretation of a highly restrictive policy is intended to give Japan greater flexibility to support the presence of the United States in what is rapidly becoming a more unstable Asian region.
This wider context was taken up in alarmed comment by Chinese and South Korean government spokesmen. Mr Abe has pointedly affirmed Japan's nationalist tradition since he returned to power in December 2012 and this move seems to be part of a pattern in which it will be more assertive. Continuing tension over the Sendaku/Diaoyu islands disputed with China, together with Mr Abe's reference to sharp exchanges between Vietnam and China arising from oil drilling near disputed islands in the South China Sea, underline that his policy shift could be militarily consequential.
President Barack Obama has affirmed that the Sendaku/Diaoyu islands are covered by the US defence treaty with Japan if they are attacked by China. Mr Abe's move would allow Japan provide logistical support to US forces during any Korean crisis and increase intelligence, surveillance and reconnaissance support for its ally in the region. These are important considerations for the US military.
Politically they are part of Mr Obama’s efforts to gain Mr Abe’s support for the Trans-Pacific Partnership trade deal, which is wavering because of continuing Japanese resistance to reducing high agricultural tariffs. The deal does not include China and is seen there as part of a US effort to contain its rising economic power. Chinese interpretations of these Japanese defence moves, along with the US defence guarantee, seem likely to reinforce the impression that this is a two-track strategy.