North Korea has already demonstrated that their ICBMS have a range that can reach anywhere in the USA. They recently launched a missile that flew OVER Japan, they have vowed to launch from 4 to 12 missiles around the perimeter of Guam. Just yesterday they detonated an H-Bomb with 6 times the power of the bomb dropped on Hiroshima. That H-Bomb was shown before being launched, and is a very small peanut shape that can fit onto one of their ICBMS.
Now North Korea is preparing to launch another ICBM. That "I" stands for "Intercontinental".
At this very moment, North Korea could nuke San Francisco with a bomb 6 times the power of Nagasaki within 30 minutes.. and could nuke NYC in about an hour. Keep in mind that Kim Jong Un has total and absolute power in North Korea.. and that he has ruthlessly killed off his own uncle and brother and other family members and his top advisors and friends. His favorite method of execution is to fire artillery shells at them and blow them to bits. Is there any doubt that he would not hesitate to attack the USA? Or Guam? Or Japan?
Then you have China.. whose economy is now going into the toilet for the first time. They insist that there cannot be regime change in North Korea. Considering North Korea is almost all barren land with pretty much just the capital city of PoonTang where Kim Dung Un lives.. how does NK get attacked without taking out fat boy?
Here's a theory.. China is propping up North Korea to be a massive pain in the world's ass.. And China will invade North Korea to "take control and stablize it" and then go on to take over South Korea as well. http://www.foxnews.com/world/2017/09/04/north-korea-reportedly-appears-to-be-readying-for-new-launch.html