EAST Asia marches on towards potential confrontation while the rest of the world looks on with apparent insousiance. The latest step along this road is Japanese Prime Minister Shinzo Abe's move to revise the official "interpretation" of the postwar Japanese constitution.

Mr Abe presents this as a move designed to enable Japan to fulfil its global responsibilities by allowing it to come to the aid of allies in the event that they are attacked, and to engage in "collective self-defence" - thus making Japan a more "normal" country in this regard. But it is not so much the content of what he is proposing that provides ground for concern as the context in which it is being proposed. That context is defined by a more nationalist Japan and by China's growing projection of its maritime power and territorial ambition in East Asia.

It is also the manner in which Mr Abe's move is being made that gives rise to unease. By reinterpreting the constitution, he hopes to avoid the need for a formal "amendment". The obvious "ally" to whose collective self-defence Japan would be expected to contribute in an emergency is the United States, with which Tokyo has a mutual security treaty. It is no surprise, therefore, that Washington is supporting a more proactive role by Japan. It is possible to envisage situations in which the US could come under attack from North Korean missiles overflying Japan, which Japan would be in a position to intercept by engaging in collective self-defence. Also, threats to US ships attacked near Japan could be countered.