Interesting. I wonder what the goal(s) would be of the preemptive strike. When Japanese preemption was mentioned previously, it was in the context of hitting missile sites as missiles were being fueled with the goal of interrupting the launch of those missiles.
In this case of a preemption for the test of a nuclear weapon, however, I would be very interested what the goal(s) would be. If the goal is the same, preventing the activity, then that will likely require some significant commitment on our part.
I'd imagine the goal would be to completely destroy the NK capability to ever even THINK about making another nuke.
The little nutso simply cannot be allowed to have possesion of a bomb.