The world has no choice but to live with a nuclear-armed North Korea. The US — by choice and default the crucial counterbalance to the rogue regime — cannot change this fact without taking catastrophic risks. That does not mean the US has no options.

Its goals should be to maximise the deterrent forces acting on Kim Jong Un, the country’s pitiless dictator; make further development of his nuclear weapon programme as difficult as possible; and to keep alive the possibility, however faint, that in the future the hermit kingdom might accept limits on its nuclear ambitions in return for an end to its isolation.

On Sunday North Korea conducted by far its largest underground nuclear weapon test, which followed the firing of a long-range ballistic missile near Japan. Since then, President Donald Trump and his advisers have let the possibility of pre-emptive military action hang in the air. Defence secretary James Mattis, for example, has stated that “any threat to the United States or its territory?.?.?.?will be met with a massive military response”. Whether “threat” in this context refers to an attack or something short of one is ambiguous. Presumably the ambiguity is intentional. But pre-emptive attack would probably end in a massive and unacceptable loss of life.