It's to each person's speculation as to whether or not North Korea could deliver such a blow to the United States but if our defensive weapons did not intercept an incoming attack and given North Korea's boasting the article listed above could give some unsettling thoughts. I, for one, believe this nut over in North Korea is one that might just attempt such a thing if he thought for a moment he could succeed at doing so. Many are so scared of Trump and feeling that he would get us into World War III but if North Korea is successful developing such weapons then I believe we should assume he would use them.
The cat, so to say, is out of the bag because they have the technology whether it came from China or other nations or that we allowed them to develop it and I also have no doubt that if North Korea has it then Iran could very soon have it also.
There is much that most citizens don't really know or have knowledge of and I believe that is a good thing. Many wonder why a President ages so much in office and I think much of it has to do with the fact that he, as one of a few, know full well what threats exist in our world and just how fragile peace and life can be and knowing that a great deal of that rest upon their shoulders. I would hope that our nation's leaders have put enough into defensive measures so that we could intercept an incoming attack but as I understand it from various reports there isn't a great confidence in many people's minds that we could intercept all incoming threats and that some would make it through if such an attack occured. Given that I can only assume that the chances of a preemptive attack is much greater than at any time before and the real question then would be what would China and/or Russia do? I feel at times that this sounds like the Chicken Little tale. I just hope there are enough sound minds to prevent such an event.