across? >> reporter: -- relations between the u.s. and north korea have taken a nosedive. the north has not moved to denuclearize, instead, conducting one short-range missile test after another. earlier this year, kim issuing an ultimatum, demanding the president loosen punishing economic sanctions by the end of the year or else. the u.s. hasn't budged, and now, a top north korean official saying, "it is entirely up to the u.s. what christmas gift it will select to get." president trump making light of it. >> maybe it's a nice present. maybe it's a present where he sends me a beautiful vase as opposed to a missile test, right? i may get a vase. i may get a nice present from him. you don't know. you never know. >> reporter: tom, after three high profile meetings and an enormous amount of political capital spent, we are back to the status quo of 2017, with president trump calling kim rocketman and north korea again rattling its sabres. now, what analysts tell us makes this situation so potentially