That is detectable with radars and some other tech stuff
That is way once NK Does send a nuke to the west side of USA the worst part isn't the buildings getting destroyed its the chemicals that get released from the bomb causes radiation
Please, stop. You are making yourself look more idiotic by the day.
Any missile, nuclear or not, wouldn't come within 600 miles of the US coast. Saying anything different is like saying apples don't grow on trees. The USA has spent millions on systems that are ment to make sure nothing ever touches soil. And if the system failed for some reason, they would just scramble jets and blow it clean out of the sky. And then, once it was confirmed that it was from NK (And it would be confirmed in less than 10 minutes.) or it's allies, hell would break loose and they would instantly regret it. If it came from NK, bombers would launch from Japanese joint AFB's and decimate any threat in less than 10 hours.