North Korea is in reality a complete puppet state of China. They always have been since the Korean war. It was CHINESE troops, millions of them, that pushed the UN/US forces back across the 38th parallel. What do you think they did after accomplishing that? Packed up and went home and said 'well you're welcome DPRK for us winning your war for you"? Nope, the reality is the PRC has been secretly in charge of DPRK EVER SINCE. Why do you think the DPRK all has CHINESE WEAPONS, from AKM rifles to the same ballistic missiles? Do you really think a country that can't manage to manufactur enough tractors to feed their population is capable of building nuclear reactors? Nope.
The FACT is that the People's Republic of China has been arming North Korea to the teeth for a REASON. They have installed thousands of ICBMs, each with multiple warheads in North Korea. China is in complete control of them. When China decides the moment is right, they will launch them from North Korea at the USA!!! By doing that, China has found a way to get around that whole "Mutually Assured Destruction" thing --- this attack would come from "North Korea", so the USA would not launch a retaliatory strike against China! Even if the USA knew what was going on, they would be affraid of doing a retaliatory strike on China, because they would be affraid of a punitive nuclear strike from Russia and a second wave of attacks from China itself!
So China is ready to go with thousands of nuclear missiles against the USA which it will be able to launch with IMPUNITY! Their plan is to follow up with a GROUND INVASION of the USA. They have about 5000 container cargo ships. Each cargo ship can easily transport 10,000 infantry soldiers and their gear. That is 50 MILLION infantry troops, or fewer troops and then use the other cargo ships as DECOYS or to transport more supplies. There would be NOTHING to stop them because much of the American Military would be out of action!