Hey - if he can backflip on cancelling NAFTA - then he can back down on flattening North Korea.
The man is utter p1ss and wind.
Like a lot of bullies - I reckon he's secretly the grossest of cowards.
If it ever really came to a shooting war with the Norks, he'd be hiding under the table in the situation room, cowering.
Syria is no parallel - a little chat with Vlad beforehand so that the MiGs, Hinds and Frogfoots could be shifted out of the way and then badda-boom - some sound and light to appear tough.
This... is a little more complex, and there isn't the same room to move.