Actually, there are some 10,000 artillery pieces currently targeted on Seoul. How many people live in that city? I know that it's in the millions. Even if the US were to somehow get every last one of those guns, at least 1/2 would have the chance to fire at least 1 round... 5,000 artillery rounds falling on a heavily populated city isn't a good thing.
Mark
But not as bad a single nuke, even a baby one.