Reuters: North Korea fires missile over Japan that lands far out in the Pacific.

A Google search with “Kim threatens EMP”  retrieves many secondary news outlets, but none of the first tier. Quoting the Toronto Sun,

The North said it had tested an H-bomb that was “a multi-functional thermonuclear nuke with great destructive power which can be detonated at high altitudes for super-powerful EMP (electromagnetic pulse) attack according to strategic goals.”

In recent threats of annihilation of the U.S. and Japan, North Korea has used extreme language. We have to look at the possibility that Kim’s logic is different from what we assume with state actors that don’t use that kind of language. With the sole exception of North Korea, the nuclear powers assume that these ideas are mutually accepted:

• Nuclear weapons have no political purpose.
• The consequence of use to destroy another power is self-destruction.

This is the basis of MAD, mutual assured destruction. Like  balance of power in the 19th century, MAD has been credited by many for the longest era without general war. But now a state actor has indicated by language that it does not adhere to these principles of peace. The language could be a bluff. North Korea could secretly subscribe to MAD. But there is no way to know. Let’s now consider what Kim’s alternative logic may be. Exclude unbridled madness. It’s possible, but then there’s nothing to analyze.

This alternative logic  is based on analogy with the internal loyalty ranking system, Songbun, which applies to individuals and their extended families. This system applies extreme penalties, including starvation, to the lowest ranking 30% of the population.

North Korea’s problem:

• Diplomacy no longer offers an avenue for nuclear state acceptance.
• The newly imposed sanctions are not tolerable in the long term.
• North Korea must be accepted as a nuclear state. All means that do not result in destruction of the state may be considered.
• Songbun applies extreme penalties to large segments of the population, a widespread material aggression with material substance by the state against the individual.
• The foreign-relations analogy to Songbun material aggression is physical aggression against enemy states.
• North Korea has accomplished many small-scale acts of aggression against South Korea, and the U.S., without retaliation.

The solution:

• Prepare an  analog to Songbun material aggression to use against Japan and the U.S.
• The analog must be severe, but not symmetric with the MAD scenario. It cannot have a symmetry that would cause the attacked state to invoke the MAD response.
• The option is EMP attack. See North Korea ICBM & EMP Attack.
• The first target of choice is Japan. This provides three layers of safety against a MAD response:  asymmetry with MAD, Japan’s lack of a nuclear deterrent, and a low angle trajectory that passes beyond Japan.
• The attack must not, by technical error,  be symmetric with a MAD retaliation. The trajectory of the missile must guard against low or ground burst of the nuclear weapon.
• An attack against the U.S. by a suborbital weapon has none of the three layers of safety. An orbital warhead will be used.
• A non-attributable nuclear attack, possibly a decapitation strike via a smuggled weapon, may be acceptable.

Quoting Reuters,

North Korea fired a missile that flew over Japan’s northern Hokkaido far out into the Pacific Ocean on Friday, South Korean and Japanese officials said, further ratcheting up tensions after Pyongyang’s recent test of its most powerful nuclear bomb.

The flight path of a ballistic missile is called the “trajectory.”  When a missile or baseball is thrown by the hand, you can pitch it high, or pitch it low. It is determined at the moment of throw, or in the first few minutes of powered flight by a missile. Thereafter, and unlike a cruise missile, a ballistic missile proceeds on a fixed course. Advanced powers can maneuver the reentry vehicle, but North Korea cannot.

By tracking the missile during the phase of flight when the rocket engine is still burning, North Korea can know with high certainty how the missile will pass over enemy territory; at what height and angle. Once it is determined that the impact point would not be in the territory of the enemy, the nuclear warhead can be detonated at any time with assurance it will be at high altitude. A low-angle trajectory, passing over Japan at high altitude,  is inherently safe against ground impact.

Without detailed knowledge of the trajectory of the recent launch these are the possibilities:

• An intermediate range missile that passed over Japan at altitude low enough for an effective EMP detonation. With the yield of the recent weapon, the altitude is not critical.
• If the missile passed over Japan at too high an altitude for an effective EMP attack, a continuation of the ICBM test sequence.
• Attack of the U.S., with asymmetry avoiding a MAD response, awaits the development of an orbiting nuclear weapon. A stable near-earth orbit provides a high degree of confidence against low altitude detonation.

The takeaway: A trajectory may be observed that is compatible with an EMP attack against Japan. With the possible alternative logic explored above, it may not be a continuation of missile development. It may be an attack rehearsal.

Attack rehearsals have been carried out as drills by other nuclear powers. But never have they been accompanied by language that tempts MAD. If Kim employs an alternative logic, he may think he can get away with it.