In the news this morning, North Korea is developing a missile that could hit the US in two years. That’s a mighty slow missile if it takes two years after firing to travel from North Korea to the US. Most missiles would take 90 minutes or less.
More seriously, North Korea is not the real threat, North Korea’s friend and ally, China, is the real threat. When North Korea started to lose in the Korean War, China send volunteers to fight the US and UN troops. China already has a sizable Korean community living in China, just north of the Yalu River. I doubt that China wants an influx of Korean refugees from the North during a second Korean War. China possesses many more nukes and missiles than North Korea ever will. If Trump launches a preemptive strike, North Korea will strike back and probably invade South Korea. It is a war we cannot win. Casualties will be in the 100,000s or millions if nuclear weapons are used.