Obviously I don't think he's going to wake up one day and obliterate NK, but what happens when NK does another test--maybe an aerial test to really flout the world and show off a mushroom cloud--and Trump's reaction is to lob some missiles at their known nuclear sites? Lobbing missiles is what he did when he got angry seeing dead kids on cable news, it's not out of the realm of possibility. Is that when Seoul starts getting shelled? What do we do if thousands of people in Seoul start dying?
Update: This is Trump's statement about the news...
https://twitter.com/AP/status/895003246372294657
> If NKorea escalates nuclear threat, 'they will be met with fire and fury like the world has never seen.'
Still want to bet on his rational reaction thought process?