So far, it’s a war of words that USA and North Korea has been waging for quite some time.
North Korea does not have an appropriate response for a full scale attack form us allies in the Korean peninsula. Despite what CNN and major news outlets tell you, NK is a very poor country, and can’t handle a war with USA and his allies. If NK for some stupid reason decides to launch a a nuclear warhead on US or any ally, military intervention will topple the repressive regime within weeks.
1. Firstly, the Nuclear War will never happen between USA & North Korea. Kim Jong Un will not like to evaporate in air. China will also never like such a thing happening near their border & would show off as mediating at the time of peak tension (while in fact China would be telling Kim that the time to behave has come).
2. Even if Nuclear War happens, neither China nor Russia will participate in it. At that time, they would also like to get rid of Kim. But they would surely show off their anger against USA.
3. If North Korea starts the nuclear war with whatever missiles it has (I doubt if its missiles can reach USA- Hawaii or Main Land? It is also possible that all its missiles are bogus.), counter attack by USA will definitely wipe away North Korea’s base.
4. Even if North Korea does not start a war, USA will have to do it to call the North Korea’s bluff, but with conventional bombs & not Nukes.
5. For both 3. & 4. above, Trump shall have full US public support as he shall claim (& rightly so) that he has pre empted Pearl Harbor or 9/11 type attacks.
6. China’s position shall be weakened if 2. to 4. above happens. Possibly, the two Koreas shall unite under US protection.