I. North Korea has apparently developed nukes that could reach Guam - a U.S. territory in the Pacific. This has caused our President to threaten them.
II. If they actually attack Guam, that would be bad and possibly a declaration of war.
III. Japan and South Korea who are right there and US-backed would attack rather swiftly.
IV. End of North Korea unless they attack Seoul, which is 30 miles from the DMZ. Then you get World War III.
.
While the US military obviously has the ability to erradicate North Korea with nukes, that's not going to happen. It would be morally inexcusable to kill all the innocent population.
.
What is very likely, though, is tactical strikes on all their military installations at the same time, using cruise missiles and other short range guided explosives. The security of the South Koreans across the border has to be paramount. Also Japan's safety is a key factor.
.
They have been boring tunnels into their mountains for the past 50 years in North Korea so they have a lot of places to hide mobile missiles. But the entrances to these places can be wiped out with bunker-busting bombs.
.
The little fat boy dictator with the volley-ball head haircut would be making a very serious mistake by launching Intermediate Range Ballistic Missiles toward Guam, even if he announces in advance where they're going to splash down in the ocean before reaching Guam. It would be his last mistake.
.