Jeffrey Lewis states  something obvious that many people in the U.S. don’t want to admit:
There are really two assessments in the Post’s report. One, dated July 28, is that the intelligence community — not just the Defense Intelligence Agency, contrary to what you may have heard — “assesses North Korea has produced nuclear weapons for ballistic missile delivery, to include delivery by ICBM-class missiles.” The other assessment, published earlier in July, stated that North Korea had 60 nuclear weapons — higher than the estimates usually given in the press. Put them together, though, and its pretty clear that the window for denuclearizing North Korea, by diplomacy or by force, has closed [bold mine-DL].
These judgments are front-page news, but only because we’ve been living in collective denial.
In response to the recent U.N. Security Council vote, North Korea’s government stated that it would not negotiate  over its nuclear or missile programs. The assumption that seems to be behind Trump administration policy is that they can be cajoled into doing this, and furthermore that they can be pressured into making concessions on these issues  before talks begin. The administration is laboring under the delusion that it is still possible to persuade North Korea to give up on things that its government considers essential to its security. If anything, the heightened tensions and increased pressure in recent months have just confirmed their leadership in the belief that they need their nuclear weapons and missiles more than ever. Needless to say, talking about raining down “fire and fury” on them isn’t going to make them more likely to compromise on this point.
One of the more common hawkish refrains about North Korea is that “diplomacy has been tried and it failed,” but this ignores that North Korea acquired nuclear weapons in response to some of the same pressure tactics  that hawks wanted to use in lieu of the nuclear deal with Iran. There was a diplomatic agreement in place that had succeeded in limiting North Korea’s nuclear program, but the Bush administration wasn’t satisfied with it . They blew up the agreement , and North Korea withdrew from the NPT and tested its first nuclear weapon soon thereafter. North Korea is a cautionary tale about what happens when hard-liners in Washington prefer to scrap an imperfect but working nonproliferation agreement in favor of pursuing the fantasy of forcing the other side’s total capitulation. It is why we should appreciate the successful nuclear deal with Iran, and it is why much-derided diplomatic engagement with North Korea is the best way to reduce tensions and manage the new reality bequeathed to us by short-sighted hard-liners over a decade ago.