There's a good deal of unwarranted fear-mongering in this article, as there frequently is when North Korea's missile program is the topic. To take the author's hyperbole at face value, North Korea could launch a nuke at the USA today! That is not the case and it's unlikely to be the case for a long time, if ever.

North Korea has never even test-fired an ICBM, let alone developed them to the point of reliability. Then there's the matter of miniaturizing a nuclear weapon so that it can be carried by an ICBM. Each one of those tasks is a lengthy and highly involved undertaking. I don't say the North Koreans can't get there one day. But there will have to be a whole lot of testing of both the ICBMs and their miniaturized warheads before NK has a credible deterrent.