Australia has only one agreement that automatically commits us to war and it isn’t ANZUS. At the signing of the armistice in Korea in 1953 we agreed, with South Korea’s allies, that we would defend the South in the event of an attack by the North. It had nothing to do with the US alliance, but rather is a UN commitment. It was associated with a set of non-aggression pacts which were repudiated by North Korea in 2013. At that time a UN spokesperson said the pacts couldn’t be unilaterally repudiated under terms registered with the UN and that Pyongyang was considered bound. The stakes for Australia are high indeed.

President Trump has been gripped by the North Koreans’ steady progress towards an ICBM that could reach the continental US. His ‘never going to happen’ pledge publicly established a ‘red line’; it will be a litmus test of his credibility. The issue’s unique status is underlined by the president’s apparent willingness to read all related briefs and intelligence reports. If diplomatic efforts, ramped up sanctions and Chinese persuasion fail, then Trump has made clear that military options will be seriously considered.

The Trump red line hasn’t been extended to shorter range missiles or the nuclear program generally. However, military pre-emption associated with it would significantly raise the prospect of a North Korean response making consideration of even broader pre-emption necessary. That could spell devastation for South Korea and cause massive damage both to Japan and to US bases in Japan and Guam. A major war would result; minimising those consequences would be the main task for the allied military. A subsequent North Korean attack on the South would engage Australia’s 1953 armistice obligations.

Trump’s red line is drawn on a situation Asia understands well. He has put American credibility on the line. To the North Koreans he has said that he would be ‘honoured’ to engage Kim Jong-un in discussions on nuclear matters, making clear that regime change in Pyongyang isn’t on his agenda. Nonetheless, North Korea presses on.

With the Chinese, Trump has deployed a range of carrots and sticks, all of which carry their own implications in the minds of Asian leaders. The stick is that China, a longstanding enabler of North Korea’s program, faces the prospect of a war on its border and a harsher American attitude on bilateral issues. The carrots have been extraordinary: a walk-back on Taiwan, a trade agreement, a retreat from freedom-of-navigation patrols in the South China Sea, and an effective enhancement of China’s regional status (the opposite of Trump’s stated intention in the presidential election campaign).

Despite paying close attention to briefings, Trump appears not to have grasped the regional context. The ally most affected is South Korea. Seoul has been roiled by an apparent presidential indifference to South Korea’s fate in all this. Nothing the president has done has allayed local concerns at what they call the ‘Trump risk’.

Consider here the extraordinary series of comments and initiatives by Trump in the last month of the South Korean presidential campaign. First was the announcement that a carrier task force—an ‘armada’ in his words—has been dispatched as a signal that Pyongyang’s actions could draw a military response. Fear, then ridicule, was the reaction in South Korea when its appearance was delayed.

Second, Trump erroneously opined that South Korea had once been occupied by China, reinforcing a South Korean view that he knew nothing about them. He also indicated that it might be necessary to renegotiate or repudiate the US–ROK free trade treaty.

Finally, having deployed the THAAD missile defence system—a controversial move in South Korea and heavily related to the defence of American troops in the region—Trump claimed that South Korea should pay. All of Trump’s interventions roiled a South Korean presidential election campaign in which Moon Jae-in, the overwhelming winner, sought to reset the Seoul–Pyongyang dynamic.

The risks of a pre-emptive strike are acceptable to Trump. However, the red line is limited. A freeze of the contemporary position with strong verification might just be possible (though it isn’t on the table currently). Such a deal would stop North Korea’s nuclear weapons program short of an ICBM, but it would massively complicate the global non-proliferation regime. The Iran deal was doable in part because Tehran’s public position was that it didn’t want a nuclear weapon. Kim Jong-un is way beyond that. Fig leaves would be necessary. Somehow North Korea’s six-party commitment not to proceed to a nuclear weapon would have to be in any agreement.

China will underperform. Beijing won’t get the North Koreans to a complete rollback or to a negotiation focused on achieving that goal, so vital to the non-proliferation regime. It isn’t vital to Trump, who is overwhelmingly motivated by perception. North Korea not proceeding with an ICBM gets him there domestically.

For the rest of the region, it’s important to cool the situation. Lessons, however, have been drawn. South Korea, Japan and Taiwan are developing their own local defences and defence industries. This experience will accelerate that trend. Lessening dependence on the US military is now on the agenda in all three countries. But that is long term.

In the meantime, the trio seek breathing space. Return the US deterrent to a latent status. It shouldn’t be at the forefront of diplomacy but credible enough should Pyongyang consider a more active approach to its nuclear ambitions. Seoul, Tokyo and Taipei now hope they can lift the threshold of that eventuality.