After all the promises of fire and fury, the threat and the counter-threats, Thursday’s announcement that Donald Trump is to meet "Rocket Man" Kim Jong-un by May is an extraordinary, historic moment in global politics.

It was also inevitable.

Mr Kim’s entire strategy has been building to this hour while Mr Trump’s options have been thin throughout (even if they all remained on the table, as he and his officials were so fond of saying).

Any reading of the past year suggests Mr Kim has played a blinder in plotting a course for wannabe nuclear powers to follow.

He made acquiring nuclear weapons the only goal of his brutal administration. His calculation was simple: Once he had nukes his family was safe from the sort of regime change seen in countries such as Iraq and Libya that gave up their programmes to develop weapons of mass destruction.