Trump needs Kim to behave (not test fire missiles) until after the 2020 election. No one wants to go to war. If you are locked in a cage with a mad dog you can either talk nicely to him until you can get the door open hoping he doesn't bite or you can kick him and be reasonably sure that he will bite. I agree that Kim will probably never denuclearize. I am sure he has read The Art of the Deal. He will play us against China and Russia any way he can.