North Korea has continued to challenge its adversaries, creating very dangerous international tensions on the north Pacific Rim, even if its latest missile test failed in a dramatic explosion upon launch. It still has the capacity to threaten a large part of the globe, and the US has sent an aircraft carrier strike group to the region.

American President Donald Trump has been very blunt saying that the US will rein in North Korea’s nuclear programme if China cannot do the job. The danger is that the new US president will be emboldened by his actions in sending missiles into Syria and a vast bomb into Afghanistan to take some kind of precipitate action that might trigger a major crisis for which the US and its allies are not remotely prepared.

There is no doubt that the rogue regime of Kim Jong-un does not deserve to continue. His brutalising of his own people and the threat he offers to regional and world peace are ample reasons for him and his entire regime to go.

The South Koreans have a very thorough Ministry of Reunification that has planned through scenarios ranging from the most unlikely peaceful reunification by mutual agreement, right through to being ready for the abrupt end of the regime and coping with a humanitarian crisis the like of which has rarely been seen.

The collapse of North Korea will involve the south taking charge of a semi-starved population of 25 million North Koreans, of whom more than 20 per cent have been kept in prisons or concentration camps to be available as cheap labour for the rest.

All this may be a long way in the future, but has to be an integral part of any strategy attached to a major American military challenge to the North Koreans.

Trump’s administration cannot go it alone on this issue as it did in Syria and Afghanistan. It needs to work with the South Koreans in particular and the Japanese.

Any successful action will need to be effective and coordinated with the two leading US allies in the region.

It will also be important to keep the Chinese closely informed at all points, and such a courtesy to the Chinese does not imply allowing any Chinese veto over action, but would be a practical step in making sure that the dominant power in the region is informed and may be ready to help in some way.