Trump has a bad habit of bluffing-- bluffs that he cannot really do. It may come from business where old style negotiators would  walk out of a negotiation-- often loudly asking someone to shred all the notes and agreements after he leaves. But that does not work in a situation like the Aircraft carrier that wasn't there. In this case threatening what sounds like it might be a nuclear attack if NK "threatens us" is a bluff which he cannot carryout-- we are not ready for it militarily and Congress (Republican leaders) have said that attacking and invading North Korea and going to war will require approval of Congress.  NK knows this is a bluff and they immediately mad a threat to send rockets to Guam knowing that Trump is not pepared to do anything. The Asian tradition is that only losers bluff-- if you are strong you never need to bluff. There is danger that getting into a battle of bluffs with NK will lead to war, delay to the advantage of NK and kill negotiations.