It is a given that in the event of any exchange/attack/altercation that Seoul and the surrounding area will be removed from the earth by the many means the north koreans have aimed there day in and day out.

That will happen in the heart beat that it will take for the USA to launch an all out attack and stop the north koreans from doing any more....ever again.

The collateral damage will be in the millions.

It is and has been the main deterrent to taking action against the little fat rocket man.