I am curious why people always assume MAD is in play with NK. Both China and Russia have now condemned NK, and pulled support "officially". They will not step in to help out if NK attacks. Even if The US attacked first neither would do anything but bitch. We won't attack first though, that would be bad for business. You see, the sanctions on NK are designed to do one of two things, get them to stop making a valid nuke, or force them to attack out of desperation.
If NK attacks there will be loss of life somewhere, and the US military will be justified in using highly classified tech to glass North Korea. The usage of this non nuclear tech will at first be championed as genius as no US triops will need to die, but in truth it will lead to a new world wide arms race and the militarization of space. This will be very good for the powers that be due to the massive amounts of money to be made off the blood of millions of lives.
Trump likely sees NK nuking California as a good thing politically, and will allow it to happen so he can use the toys that will make his family even richer.
If you are curious what I am talking about look up rods from god.