We are used to painting North Korea as "unpredictable", but Kim Jong Un's single-minded determination to develop a fully-fledged nuclear deterrent has defined a remarkable continuity to his six-year rule, setting aside the question whether the young man's motivations are defensive or aggressive.
With Pyongyang hell-bent on acquiring a capability to directly threaten the US homeland with nuclear attack, inevitably there would come a point at which this became an urgent, security concern for Washington, irrespective of official reluctance to admit a North Korean pretender into the exalted ranks of existential threats. That was the obvious flaw in the Obama administration's "strategic patience" approach, as it became steadily clear that a catalogue of sanctions and stern warnings would not deflect North Korea from pursuing its strategic ambitions.
North Korea would be a pressing priority for a president Clinton, as much as it is for the Trump administration. The difference is that under President Trump, the US has itself become the major source of strategic unpredictability. Trump's increasingly shrill rhetoric on North Korea is feeding a dynamic that plays to Pyongyang's practiced strengths in escalation dominance.
And as the cycle of threat and counter-threat plays out, war is not the only risk. Unheeded warnings and bluster do substantial damage to US credibility with negative implications beyond the North Korean situation, for the more important US-China strategic contest ahead.
Where Pyongyang has consistently surprised, under Kim Jong Un, is in the exponential technical progress resulting from a barrage of missile and nuclear tests, and the bewildering variety of delivery systems now under development in North Korea. These include submarine-launched missiles capable of reaching Guam, and intercontinental ballistic missiles (ICBMs) that potentially place large swathes of the US mainland within range.
Before they can credibly announce a "battle-ready" nuclear deterrent against the United states, the North Koreans still have multiple rounds of testing ahead, including a crucial requirement to validate the survivability of missile warheads as they re-enter the atmosphere. Yet the US Defense Intelligence Agency already assesses that "North Korea has produced nuclear weapons for ballistic missile delivery, to include delivery by ICBM-class missiles" and may be "in possession of enough fissile material for 60 nuclear weapons", with capacity to add 12 nuclear weapons per year to this deadly arsenal. To be clear, Kim Jong Un is not settling for a just-enough-essential-parts nuclear deterrent; he wants the Rolls Royce.
Not everyone has been surprised by this high level of ambition and progress. The high-ranking diplomat defector, Thae Yong Ho, who fled the North Korean Embassy in London for South Korea a year ago, made an early prediction that the North Korean regime would make an all-out push to attain its nuclear and missile goals in 2017. He judged that Pyongyang saw a window of opportunity opening up with the US and South Korean presidential elections, with the potential for policy vacuum to ensue. Mr Thae has been proven right, though no-one could have foreseen the levels of policy disarray unfolding in Washington, six months after Trump's inauguration.
While President Trump has shown no inclination moderate his language on North Korea, doubling down instead on his "fire and fury" comments from this week, it has been left to his foreign and defence ministers to interpret the commander-in-chief's comments.
Secretary of State Rex Tillerson downplayed the situation, saying there was "no imminent threat of war". Defence Secretary James Mattis' written statement, however, was harder-edged, warning North Korea that it is "grossly overmatched" in military terms, and would "lose any arms race or conflict it initiates", spelling the "end of its regime and destruction of its people".
In Mattis' defence, he was put in the unenviable position of putting the President's "fire and fury" comments into context. However, if Mattis' intention was to send a clear-cut message of deterrence, the unintended consequence of communicating with Pyongyang in such terms may simply be to hand the regime a pretext for an accelerated program of nuclear and missiles tests. This, in turn, will spark renewed questions around US credibility, raising the stakes further.
In reality, the chances of the US initiating "preventive" conflict on the Peninsula are slim. There are no indications of a substantial build-up of US forces in Korea, Japan or surrounding waters. Nor are preparations obviously under way to evacuate US citizens and their dependents from South Korea, although Mr Trump is famously reluctant to signal his intentions in advance. While there are no rhetorical "off-ramps" in sight, the costs of war are so high that North Korea and the US will probably learn to deter each other, provided both can master the more clinical vocabulary and syntax of nuclear deterrence as it was practiced during the Cold War. Perhaps that is an unrealistic ask.
The more wicked risk is that North Korea will be emboldened under cover of its strengthening nuclear capabilities to engage in conventional provocations targeting not the US directly, but its allies South Korea and Japan. That is a more realistic pathway for how the US gets drawn into a second Korean conflict, fought in order to preserve its declining stock of credibility in Asia.