The nuke problem is really a small piece of it. More than a nuke blast or the radiation it would be the trigger that kills millions of people in Korea and Japan.
We can destroy N Korea with conventional weapons. If they even fired a missile with a nuke it would be all over. But the problem then is we would retaliate, but there is no way we would be able to take out all the artillery and missiles aimed at Seoul. All of those would be launched immediately and millions of people in a huge modern city would be killed. And who knows what other targets in Japan and other areas would be hit.
With most military actions there would be a huge buildup of soldiers and weapons, we would have some time to evacuate or secure civilians, increase defenses. But that isn’t happening.
The scariest thing for me is that one of these two crazy idiots would pull that trigger. And I’m most afraid that idiot would be Trump acting preemptively. By hyping up the nuclear threat to the US he’s getting the support from his base to do it. And this could happen any day.
But the removal of Kim Jong Un or his nuke program would be at the cost of millions of our friends and allies.