Sam Rogeveen's  post last week about the strategic aspects of Japan's submarine bid focused on exactly the right question: What does Japan want? This is much more important to the subs decision than the question many people seem to think matters most, which is what China wants us to do.

Some think China's presumed opposition to closer strategic relations between Japan and Australia is reason enough to kill Japan's bid. For many others, Beijing's objections are the best reason to accept it. Neither are right. While we can't and won't completely ignore what China thinks, there is no reason to allow Beijing a veto if we decide, on mature reflection, that Option J serves our best interests overall. But Beijing's objections – assuming they do seriously object, which is not beyond doubt – are no reason to do something which is against our interests just because we like the idea of defying China.

So what about Japan? There is no doubt it expects a submarine deal to lead to a much closer strategic relationship, but it is less clear what exactly the Japanese have in mind, and therefore whether it would be in our interests.

I have argued that Japan seems to expect something close to a full-blown alliance, directed against China, under which Japan would be assured of Australia's support, including military support, in a crisis. Sam quotes Brad Glosserman, who says Japan's expectations may not run this high because there seems to be no enthusiasm among Japanese to depart from its old strategic posture and build a coalition against China independent of the US.

Some thoughts on this. First, we should not presuppose that Japan would only seek an alliance with Australia if it decided to strike out independently of America. In fact, it seems quite likely that Japan would see an alliance with Australia as a real asset while Tokyo remains a US ally, in part because the Japanese hope it would bolster America's willingness to help Japan in a crisis if Australia was stepping up too.

Second, while I'm sure Brad Glosserman is right that most Japanese would prefer to keep relying on the US, they may find that is no longer possible. If America proves unwilling to bear the costs of confronting China, Japan would face an inescapable choice between building an independent role as a great power or accepting subordination to China's strategic leadership.

Perhaps, for the reasons Brad Glosserman suggests, Japan would opt for subordination. That would worry Australia if we chose a different path and our submarine capability depended on Japan's support.

But it's at least as likely that Japan would decide to resist Chinese primacy. In that situation Japan really would want all the allies it could find, and Australia would be high on the list. My hunch is that this is at least part of the thinking behind Japan's enthusiasm for closer defence relations with Australia today. Not only would it reinforce Japan's US alliance for as long as that lasts; it would also be a building block for an alternative Japanese posture if the US alliance fails.

Whether it would serve our interests to ally with Japan in such circumstances would depend on how both China and Japan were behaving at the time. Australia would want the maximum flexibility to make a choice that suited us best in the circumstances. Tying our submarine capability to Japanese expectations of Australian support would very sharply limit that flexibility.

The bottom line here is that the less our strategic circumstances change, the more sense a strategic alliance with Japan makes. But the more they change, the more likely it is that an alliance with Tokyo would not be in our interests, and the greater the risk to a submarine capability that relied on such an alliance. And these are of course exactly the circumstances in which our submarines would be most important to us. A subs deal with Japan would work best when we needed subs least, and worst when we needed them most.

So it's clear that we really do need to know whether Japan does expect an alliance with Australia as part of a subs deal. We should not need to speculate about this. Tokyo needs to explain very clearly what kind of closer strategic relationship it expects to flow from the submarine deal, and we in Australia then need to debate what that would mean for us. If the Japanese are seeking serious strategic commitment, they need to say so as plainly as possible. If they are not, then let them come out now and say that, as plainly as possible. The ball is in Tokyo's court, and we'd be mad to make a decision before we have heard from the Japanese one way or the other.

Photo courtesy of Flickr user Atsuhiko Takagi