Why target Guam? Because it's a nearby U.S. territory and not a separate country like Japan.

I don't think the U.S. will do a first strike on NK. China already said that if the U.S. does that it will support NK, but if NK strikes it will stay out of it. That's a huge change from the Mao era when China supported NK's aggression. That plus the strong sanctions that China agreed to show that today's China is different. It doesn't want to get into a war with the U.S., especially since it owns so much of the American debt.

Somehow what I think needs to happen is for China, Russia, South Korea, Japan and the U.S. to form an alliance against NK. Not by going to war against NK, but by putting pressure to support those who would get rid of the Kim dynasty. Not saying that it would happen with the current set of political leaders, but with smart leaders and intelligent horse-trading, it is theoretically possible.