THAAD deployment in South Korea is merely cosmetic. This battery is based 276km south of Seoul so it can't protect anything except paddy fields. The missiles are only effective in a 120km arc. In order to be of any use they need deployment within 40km of the target to be defended because they must fly a reciprocal trajectory for the incoming missile. They have just two missile launch vehicles with eight missiles per vehicle.

North Korea merely needs to fire sixteen missiles simultaneously and then follow with a nuke and THAAD is gone. This whole thing is just theactrics because they can't defend South Korea much less Mainland USA.