I'd say that it depends which way they launch it, if they use their normal testing bearing then the ROK/Japan/US will probably just let it splash into the sea. If they try something new then they might shoot it down.
Bear in mind that shooting the missile down is exactly what the DPRK wants them to do, so it can claim that the US fired first by conducting an offensive act upon a peaceful missile test. So, it's not highly likely that the US/Japan/ROK will shoot down the missile since they don't want to play into the DPRKs hands...which of course will force the DPRK to look for another way to try to provoke the US/ROK.
|