What are you nuts? As soon as any missle from the US starts heading toward NK, they launch a nuke…they launch a nuke, we launch a nuke…China would not be happy…China then blows up the US, and we blow up China…So yeah we could preemptively attack North Korea, so long as we understand doing so would remove the west coast.
There is NO WAY we can launch a strike on North Korea…the only reason Noth Korea is dangerous is because their leader might just be crazy enough not to give a fuck if he gets blown off the map.