It is appearing more and more that
(a) Trump wanted too much to “resolve the Korea issue” that
(b) he did not get his team in place and charge that team for doing everything needed before a U.S.-Korea summit meeting, such that his team had strong agreement of a likelihood of success of some sort before an agreement for the summit was made, and
(c) that likelihood appears less and less, and
(d) Trump is in a diplomatic lose-lose situation.
He will “lose face” diplomatically if the U.S. is the 1st one to say there will be no meeting, and he will also “lose face” when they go ahead with the meeting ONLY to go ahead with the meeting, knowing and expecting no major substantive agreements or changes will come out of it.
I have said all along that there should have no announcement of any summit before the ground work for a successful summit had been done and which had good expectations of success. That is normally all done in deep background with neither party disclosing any part of those discussions until they have AGREED ON (a) a summit and (b) what will make it a success. The summit meetings themselves are usually AFTER preliminary agreements have already been reached, behind the scenes (like as Kissinger secretly did with China).
Trump’s problem is sometimes not his ideas, but his style, which pushes TOO MUCH into the public realm, and in the case of this summit meeting it is easy to see it may have all been for nothing, but its all - all the expectations - already out there and built up, by him.
N. Korean vessels may be interdicted in high seas. U.S. Coast Guards are already out there watching. Navy ships from several countries sailed into Japan some months ago. They could fan out and go into action.