We all agree that something rather important happened in Phnom Penh last month, but differ about what it portends for ASEAN, and for Asia. 

Let me start by agreeing with Ernie Bower that pessimism about ASEAN is easy to overdo. ASEAN has been remarkably successful for over four decades in managing relations between its members. In particular, it has been very effective in suppressing conflict between them, an achievement which it is easy but unwise to take for granted.

But we shouldn't exaggerate ASEAN's achievement either. It has not created or upheld the stable regional order of the post-Vietnam era. The credit for that goes to America's primacy, and China's acquiescence to it, which suppressed major power competition in Asia and which in turn has been essential to ASEAN's success.

Linda Quayle doubts that, because major-power competition continued in Indochina throughout the 1980s. But I think Linda's point strengthens my argument that low levels of major-power competition over its members have been necessary for ASEAN to work. The residual competition in Indochina was destabilising for ASEAN, but not fatal because one of the main players was the Soviet Union, which counted for little in Asia. It was however enough to keep Indochina out of ASEAN until the Soviet withdrawal. Only then, when major-power rivalry over them ceased, could the Indochinese states join ASEAN.

This explains why I am more pessimistic than Ernie about ASEAN's future, and why, unlike Ernie, I think ASEAN will do little to help America achieve its aims in relation to China.

But what are those aims? Here there seems to be a big disagreement. I see an escalation of strategic rivalry as China tries to expand its power and influence in Asia at America's expense, and America tries to stop it. Ernie sees America upholding the regional order in Asia as China aims to undermine it. But is there a real difference here, or just different ways to say the same thing?

This gets us back to our discussion here a few weeks ago about US policy towards China and 'containment'. Like Abe Denmark and many other American colleagues, Ernie is sure that America is not trying to 'contain' China, and insists that it would be foolish to do so. Instead, they say, America is just trying to ensure that China plays by the rules.

But when the rules include accepting American primacy as the foundation of regional order, making China play by the rules means making it abandon its aspirations for a larger regional role. Thus, when American colleagues say that America wants a good relationship with China, they are right, but they are also saying that they only want a good relationship with China as long as it is on America's terms. 

That is why, to pick up another of Linda's points, I agree we should not 'blame China' alone for growing rivalry between Beijing and Washington. Both carry equal responsibilities for building a stable order in Asia that peacefully accommodates them both, and each can be blamed for the failure to do so thus far.

Each can also be blamed for using the South China Sea issue as an opportunity to pursue their rivalry. Thus I do think we can blame China for what appears to be the rather reckless way it pursued its aims in Phnom Penh, just as I criticise the US for the using the South China Sea the same way in Hanoi in 2010.   

Indeed, Michael Wesley is absolutely right to say that the South China Sea has become more dangerous precisely because it has become a forum for rivalry between the US and China, and an uncomfortably probable setting for a clash between them. Carl Thayer's characteristically informative post emphasises to me that the issues supposedly at the heart of US and Chinese positions in the South China Sea, such as freedom of navigation, are really just stalking horses for the rivalry over status.

And that is why I do not follow Michael in concluding that Australia should seek to mediate these issues. Not that I have any objection to Australia taking an active role; on the contrary. But the South China Sea issue per se is not really what's in dispute. To make a real difference we have to try to help address the underlying sources of US-China rivalry. As it happens, I have a little book coming out on that next week...