At the center of mounting global concern over a nuclear strike by North Korea is one individual – 33-year-old Kim Jong Un.

After the G-20, all scenarios appear on the table.  Optimists hope pressure on China will curtail North Korean trade, reversing the apparent madman’s appetite for nuclear armed ICBMs.

Others, including Secretary of State Rex Tillerson, hope that concerted global sanctions will isolate North Korea sufficiently to trigger a rethink by this totalitarian regime.

The trajectory of North Korean activities, barring some surprise return to rationality, is like the trajectory of their missiles, unpredictable and sobering.

Institutional thinkers at the Pentagon will be reviewing "kinetic" options.  These might include a demobilizing cyber strike, effectively creating disruption, confusion and chaos – enough to deter development of nuclear ICBMs.

Further options include strikes on enabling technologies, such as launch pads and fuel storage, transport and command, control and communications.  Counter-counterforce requires simultaneously eliminating short range mobile launchers, missiles, conventional hardware.  All these kinetic options come with high risks, especially for South Korea.

Wider diplomatic options are likely being mulled, including public and private “overtures" to North Korea, signaling of kinetic events, withdrawal of diplomats, movement of military hardware and personnel, expansion of Terminal High Altitude Area Defense (THAAD) systems, encouraging South Koreans to prepare, evacuation of urban centers, and final multilateral pleas.

Closer to home, the president is restarting laggard deployment of American ballistic missile defenses, put off for a decade.  He is finally perfecting layered systems for defending U.S. territory, discussing potential deployment timelines and locations, thinking Allied and Homeland defense.

Of course, available ballistic defenses should be swiftly deployed, however imperfect.  The goal is to knock down a rogue missile.  The president should assemble a Ballistic Missile Defense (BMD) Commission, prioritize and accelerate deployment for all Americans’ protection.  But robust, nationwide BMD is years off.

Taken together, the foregoing options amount to pushing string.  They vainly hope for a return to rationality and respect for human life by someone with no apparent interest in either, a leader who is more delusional and adrift than calculating and anchored.

That said, an overwhelming military strike on North Korea would be – while possible and devastating – a nearly unthinkable choice.  History is a tough task master, especially on the Korean peninsula.

The Korean War left more than a million North and South Koreans dead, produced more than 160,000 American casualties, including 36,000 dead.  Modern realities would put tens of millions in jeopardy.  A preemptive strike would vaporize the North, leaving millions dead, but also imperil the South.

If China does not want a unified, free and capitalist Korea on its border, it must abhor even more the notion of a smoldering, chaotic, devastated Korean Peninsula.  If they believe this is possible, they may act.  China also does not want a flood of North Korean refugees, which would surely follow widespread military conflict, and might result from effective sanctions as well.

One reality weighs on all parties:  Taking no action may be more devastating than other options.  Doing nothing could leave American and Allied cities open to near-term nuclear attack, and the world open to nuclear blackmail.  Being disengaged is not an option, if ever was.

So, what is the answer to this no-win?  As economic and diplomatic pressure on North Korea and China grows, what is the endgame?  If anyone says they know, they are beyond optimistic.  The trajectory of North Korean activities, barring some surprise return to rationality, is like the trajectory of their missiles, unpredictable and sobering.

The situation demands unhesitating, decisive American and Allied resolve.  It demands unified, forward-leaning diplomacy, also military readiness, preparation for a sequence of preemptive actions and reactions, accelerated ballistic defense.

There is still time.  Expect warnings to rise.  Expect North Korea's leadership to splutter, more rogue launches, then an internal decision point.  Top echelons of North Korea’s military need to rethink the odds.

They face a no-win situation – one that could become existential quickly, produce preemptive action, erase putative gains, and should outweigh all other fears.  The course is unsustainable.

That brings us back to the start:  At the center of this senseless, unnecessary, destabilizing drama is one man, an uneasy belligerent, Kim Jong Un.  Will he see the light, or will that task fall to others?  That is the missing puzzle piece.

The North Korean puzzle will not stay unsolved.  This would be a good time for North Korea’s leadership to get a grip, for China to help them do so, and for consequences of irresponsibility to be fully contemplated.  The world will not allow nuclear ICBMs to be launched.  If Kim Jong Un has no endgame, those around him should.  Otherwise, the game will end badly – for all.