There would be no "mutual destruction." One attack could devastate us, however in minutes, N. Korea would cease to exist. He's the only president since Reagan who will use our nukes. China wouldn't respond. Russia wouldn't respond. The entire world would say, "Holy sh*t, he really did it." And that would be the end of the conflict.
There are consequences using nuclear weapons; that lovely radioactive cloud doesn't magically stop at the NK border; it's going to drift where the winds push it and many of our allies will suffer from it if it hits their country. There are no guarantees as to what reaction China or Russia would have if we start delivering nukes on their continent. Even a limited exchange could render the human species a minor or even extinct one. A conventional war is one thing, but a nuclear war will change everything. I'm not sure the world is ready for this.
Yea like all the nuclear test in Nevada hurt millions of people...who cares, nuke NK and be done with it. .
I would suggest that you read up on the effects of radiation and in particular those who lived nearby in the Nevada tests and see what the cancer rates are for those exposed to it. Your statement shows that you are being reckless with no regard to basic human safety.