NK does not need a missile to create a big problem.  They could have put one of these wmd on a barge and park in on a port somewhere.   The danger of NK has to do with its leader.  Their society seem to resemble a god king relation with most of its people following blindly.  Their military parade look evil something out of a mad mad world scenario.  The american govt usually does not act in a hap hazzard way, although it may seem.  Usual action have been planned month to years in advance depending on the threat. Only the Intelligence angencies know how far along NK nuclear capabilities are and their nuclear weapons may be much more destructive.   Trump is not acting alone,  do you actually believe, that a person that cannot put a ban on immigration entering the country  can actually push that button without getting smacked by reasonable people,  If the US act it is with desperation and with measured risk.  If the US act it is because things have really gotten dangerous for all.