Reuters: North Korea says it is ready to strike U.S. aircraft carrier. The probability that it could is not zero. The ROKS Cheonan was a small South Korean warship that was sunk by a North Korean torpedo, launched from a submarine. Perhaps to make a point, the sinking occurred 75 miles from a joint U.S. – South Korea antisubmarine exercise. The psychological aspect of the Cheonan sinking is discussed in North Korea ICBM test — Trump says, “It’s not going to happen.”.

In NBC: U.S. May Launch Strike on North Korea Nuke Test, I used Benjamin Franklin’s method as the analysis tool. Tools like this may seem utterly crude, yet they help us grapple with the otherwise imponderable. Here’s another tool, which I used to advantage in the IARPA program “Forecasting World Events”,  to predict Assad’s use of chemical weapons around the time of Obama’s “red line.” The reasoning was analogous to the aphorism, “Money burns a hole in the pocket.” The fact of possession of chemical weapons  occupies a certain amount of Bashar Assad’s mental space. To a personal dictator,  possessing the weapon promotes the desire to use the weapon.

Kim Jong Un doubtless knows the saga of the Saphir , a rather small and old French nuclear submarine that, according to reports that may have been suppressed, “sank” in exercises the U.S. nuclear aircraft carrier Theodore Roosevelt. The diesel-electric submarines possessed by North Korea do not  have the endurance of the Saphir, but make less noise, by which submarines are detected.

There are hints that analysis of the exercise produced initiatives to revise U.S. antisubmarine protocol. Nothing in open source exists to substantiate it, or allow knowledgeable estimates of current strategies. But physics is a very helpful substitute. The ocean is divided into layers of differing salinity and temperature. Each layer  contains and blocks sound from the layers above and below it. If you’d like to read the now-declassified report, it’s available courtesy of Woods Hole Oceanographic Institute as a pdf.

This is why, against the deepest veil of secrecy, one folkloric saying is widely known: The best hunter of a submarine is another submarine. The U.S. has many submarines specialized for this task. The game gets interesting:

• A dictator of little intellect has proven toys, diesel electric submarines.
• The defense against them is not apparent to him, or to us, because of extreme secrecy.
• If the dictator succeeds in damaging or sinking a U.S. aircraft carrier, his mood will be elation.  But the torpedo must actually hit.
• If the torpedo misses, the dictator sees no downside. It is his experience, with the Cheonan, that even a hit produces no retaliation.

So there is a significant probability of miscalculation by Kim, engendered by the prior failure of South Korea to retaliate for the sinking of the Cheonan. If Kim were a child, one would say he is the victim of bad parenting.

Kim  may not then understand why his fleet of submarines is then replaced by oil slicks and debris.