Domestic and global politics are ordinarily two discrete spheres. But thanks to an astonishing piece of synchronicity – rarer than a supermoon lunar eclipse – the central question occupying world leaders in Hamburg this weekend is exactly the same as the one furrowing Malcolm Turnbull's brow domestically, viz: What can you possibly do about a maniacal adversary who is determined to blow you up, and doesn't appear to have any natural limits on how far he's prepared to go?

On one front, Turnbull is grappling with the trigger-happy leader of a hermit kingdom cut off from most accepted versions of reality, constructing its own wildly revisionist account of history and operating in its own time zone with very limited access to modern technology.

And on the other, of course, there's North Korean leader Kim Jong-un. World leaders touching down in Hamburg on Friday for the meeting of the G20 – in the shadow of Kim's worrying launch of a long-range intercontinental ballistic missile earlier in the week - were understandably ginger.

For the host, German Chancellor Angela Merkel, the gathering is an Olympic-class modern pentathlon in the art of being hospitable to a bunch of blokes who have variously called her a weakling and a terrorist-harbourer, refused to shake her hand or are busily cyberhacking her approaching federal election.