NK does not need to use a nuke on the mainland US. That would certainly be responded to with an overwhelming return hit on them.
But what if one of their satellites with an EMP was detonated while it was going over the US while in its orbit.
They could just say oops we were just cleaning it and it went off or something.
That would probably cause more havoc than any hit on the mainland by a normal bomb, if they were good enough to get one that far that is.
