That nut does not need an ICBM to reach the US with nukes. He could simply load up a few of his many subs with them and park them off the west coast. In fact, there was a sub alert yesterday and planes were dispatched to search of subs off San Diego according to the press this AM.
Hopefully if they find any east of the date line, they take them out pronto.
Now think about that for a moment. What support mechanism would the Norks have for a sub off San Diego? Zip, zero, nadda. As for subs off San Diego, we are at a much larger threat of the drug runners in their almost subs which are regularly being caught or scuttled once detected.
I think his subs have to surface for air in order to get here. I doubt they would get here undetected. The nukes they have are too big, and will not fit on their missiles. They are a regional, not global power.