Clearly Japanese Prime Minister Shinzo Abe has deep personal and political motives for wanting to change Japan's strategic posture, 'escape from the postwar regime' and make Japan a normal country. But he has only been able to push this week's changes through because many Japanese who reject Abe's revisionist nationalism have lost faith in the post-war strategic posture. They can see that relying on the US has worked well for decades, but is failing now as strategic circumstances change.

The question is whether collective self-defence will work any better to keep Japan secure in these new circumstances? I don't think it will.

Japan's old posture isn't working anymore because of the shift in relative power between America and China. The stronger China becomes, the more Japan fears that China will use its strength to subordinate Japan, and the less confident the Japanese can be that America will always help them resist Chinese pressure. As the economic and military costs and risks to America of conflict with China go up, US willingness to support Japan's interests goes down, and it becomes less clear that Japan's and America's interests will always coincide. Japan therefore loses confidence in a strategic posture based on dependence on the US. We can see all this playing out in the Senkaku/Daioyu dispute, making it Japan's most acute strategic challenge since the Second World War.

Will collective self-defence fix this problem? The argument that it will is simple enough: Japan will strengthen both America's willingness and its capacity to support Japan against China if it does more to support the US against China. This is the classic burden-sharing idea that has been central to the way alliances around the world have been seen to work for the last century or so. It has certainly been central to the way Australia has approached alliance management with both Britain and the US. Indeed Japan's alliance has been unique in not imposing this kind of burden-sharing, so Abe's move simply brings Japan into line with other US allies. 

But collective self-defence will only reinforce US strategic guarantees to Japan and restore Japan's confidence in the alliance if it deals directly with the factors that have been eroding them.

On the military side, Japan's armed forces will make little difference to America's ability to win a war against China in the western Pacific. Very simply, even with Japanese support America could not achieve sea control against China's formidable sea denial forces, and even without Japan's support it can easily achieve sea denial against China's feeble sea control forces. So Japan's help would do nothing to break what is essentially a US-China maritime stalemate in which both sides can deny the waters around China to the other. And Japan can do nothing to help America control the very real risks of escalation which that stalemate produces. So Japan's commitment to collective self-defence will not reduce the costs and risks to America of confronting China.

Nor will Japanese burden-sharing make much difference to America's willingness to bear those costs and risks on Japan's behalf. America already has strong reasons to support Japan and preserve the alliance; it is after all the essential foundation of US primacy in Asia. The present crisis of confidence in the alliance arises precisely because the costs and risks of confronting China are now so great that they threaten to outweigh even this alliance in US strategic calculations.

And it is not clear that anything Japan could or will do under collective self-defence will tip the scales back the other way. Australians are familiar with the argument that big allies are more likely to come to a junior partner's aid if the junior partner has paid collective self-defence 'dues'. But this kind of moral entrapment seldom works. Tokyo would be unwise to assume that America will be so grateful for Japanese military support that they would feel obliged to come to fight China on Japan's behalf when America's own interests did not require them to do so. 

This suggests that collective self-defence as the junior partner in a US-Japan alliance will not solve Japan's strategic problems. Of course there may be a different model of collective self-defence in mind. Perhaps Tokyo intends that collective self-defence will allow it to join, and perhaps even to lead, a wider regional coalition or alliance to resist China's growing power. But that would not do much to make Japan more secure either.

In the end, Japan's best prospect for security in the Asian century is to build the forces it needs to defend itself without relying on others, and without threatening others. This is perfectly possible for Japan economically and militarily, but it would be a big step politically, and would require much better diplomacy than we have seen from Mr Abe so far. 

Photo by Flickr user JBLM PAO.