Pyongyang’s latest long-range missile test raises the probability that Washington will decide to launch a pre-emptive military campaign against North Korea, simply because it will come to see this as the only alternative to accepting that North Korea will soon be able to deliver a nuclear attack on continental US cities.

That is clear from what Donald Trump’s National Security Adviser, HR McMaster, has said, and Kim Beazley agrees. McMaster seems to believe a pre-emptive attack would be justified because the near-certainty of massive US retaliation might not be enough to deter North Korea from a nuclear attack on US cities if it acquires the capability to do so.

This is almost certainly wrong. For one thing, there is no hard evidence that North Korea is any harder to deter than other nuclear powers. It is also abundantly clear that a pre-emptive strike campaign would be unlikely to do much damage to the North’s nuclear and missile programs but it would very likely spark a major, catastrophic war that America would not win, and which could easily lead to the collapse of America’s strategic position in Asia.

But we cannot be at all confident that the Trump administration won't take this disastrous step anyway. That raises the question of how Australia would respond, and what we should be doing now to influence Washington’s decisions.

Back in August, Malcolm Turnbull promised that Australia would support America if it goes to war with North Korea:

So let’s be very clear about that – if there is an attack on the United States by North Korea, then the ANZUS Treaty will be invoked and Australia will come to the aid of the United States just as if there was an attack on Australia, the United States would come to our aid ... Now, how that manifests itself will obviously depend on the circumstances and the consultations with our allies ... But be under no misapprehension – in terms of defence we are joined at the hip ... If there is an attack on the United States the ANZUS Treaty would be invoked and Australia would come to the aid of the United States as America would come to our aid if we were attacked. That is how the Alliance works.

Turnbull’s message was ambiguous. On the one hand, he twice said ‘if there is an attack on the United States’. That appears to limit the scope of his promise to situations in which North Korea attacks first. But he also twice invokes the ANZUS Treaty, which does not plainly limit its commitments to situations where an enemy strikes first (JG Starke’s ANZUS Treaty Alliance [p.125] explores this point).

At the same time, Turnbull did not specifically commit to providing military support, and the ANZUS Treaty does not require that either. The words about ‘how that manifests itself will obviously depend on the circumstances and the consultations with our allies’ seem designed to give him some wiggle room here.

But then the ‘joined at the hip’ language seems to push back the other way, suggesting we’d support America wholeheartedly in whatever it decides to do. So too did the timing and context of Turnbull's statement, which was made when Trump was firing off wildly-worded threats of military action against Pyongyang, and was clearly intended to endorse and support those threats. That is clearly how it was received in Washington.

The obvious interpretation is that Turnbull was trying to have his cake and eat it too. He hoped that by talking tough he would ingratiate himself with Trump and impress Australian voters, while slipping in a phrase or two that he could use to slide out of the apparent commitment if push came to shove. This interpretation is supported by a fine piece of reporting from Gideon Rachman at the Financial Times last month:

Mr Turnbull has said that Australia would join a war on the Korean peninsula “if there is an attack on the US”. But Australian officials warn that the situation would be very different if a Korean war is initiated by a US pre-emptive strike. In that case, Australia would not fight alongside America ...

This raises a few interesting questions. Is the view of these officials shared by the Prime Minister? If so, is that because he thinks a pre-emptive attack it would be a mistake? If so, why? Has his reasoning been unambiguously communicated to Washington, or have our allies been left to read about it in the FT? Perhaps most importantly, if Australia’s government does think a pre-emptive attack would be a mistake, then would it not be wise to say so officially and publicly? Turnbull’s statements back in August left a clear impression that Australia supported Trump unconditionally over North Korea. If that is not so, he needs to correct that impression, and explain why.

That would, of course, annoy Donald Trump. But it might just help a little to sway the argument in Washington away from a step that would be disastrous for America, as well as for the rest of us. Doing whatever we can to avoid such a disaster is more important than pleasing the President. What’s more, Trump and his advisers would be much more annoyed if we allow them to assume Australia’s support, only to be disappointed when the shooting starts. That is the worst time to tell your allies that you are not with them.

One is reminded of Australia’s mistake in 2003, when we helped urge America into a disastrous war that did so much to destroy its position in the Middle East and to undermine its global leadership. We are in danger of making a similar mistake again.

Last month’s Foreign Policy White Paper immodestly boasted of Australia’s diplomatic weight and its capacity to shape international events to suit our interests. Here is a chance to try to justify those boasts, if we are prepared to risk Donald Trump’s frowns, by setting out a clear Australian position on an issue of major importance to us. How hollow the White Paper’s boasts will seem if we do not.