Considering the actions of the U.S, U.K and France sending their forces into what could be a global war due to the recent false flag in Douma, it seems like the best time to calculate the possibility of WWIII and its destructive potential. That being said, I personally hope that this is mere sabre-rattling and nothing more devastating than the MOAB he sent in 2017, but this may actually be the end for the entire North American heartland. Or most of it, leaving some irradiated survivors to cannibalize each other. I can see Russia/China surviving to some extent if they were to successfully attack each base before the U.S has time to react. Factor in a EMP bomb to precede the attack and too few American nukes would be able to be used. There is also a rumor that most, if not all, nuclear weapons in America are infact non-functional and have been for decades. Since the global deactivation of these warheads from the 1970s onward, they have never been replaced. Compare this to Russia [at the time USSR] which continued production all the way to the end of the 1980s where it was almost a third larger than the entire U.S arsenal during its height in the sixties. Not to forget, that Russia has mobile vehicular platforms for its warheads that could be fired from any location whereas the U.S mostly uses silo platforms that would be easily destroyed if their exact location was to be found. One could mention the bomber planes and SLBMs, yet these are not many in number and could be disabled by EMP if not shielded.