KN,
I don't think they'll start a war with s missile shot. If the start a war it's going to start with an artillery barrage unlike any other. Now, it might hit a populated because it's way off course. That's a good possibility. If the do use missiles as part of a war opening act they'll be nuke tipped and aimed at Pusan to close our port to reinforce Korea.
They may think that but Pusan is just a port and we have enough airstrips that we can use in that country to more than supply a drawn out conflict on the peninsula of Korea. If he does launch a Nuke that will spell disaster to this world in my opinion.