@ABoyNamedBoobs03, China can “survive” without us. Survival is not difficult. You can even survive in a post-nuclear holocaust dystopia. We are, however, China’s key to “prosperity.” If you think disagreements over Taiwan are so important that they can actually set off World War III, I think you’re just being paranoid.
Re: Iran, World Wars I and II were wars of attrition. Both sides of the conflict tried to kill as many people on the other side as possible. It caused unbelievable destruction and killed hundreds of millions of people. If a world war was fought today, nuclear weapons would certainly be used. To my mind, that is what makes a “world war.”
Our wars in Korea, Vietnam, Iraq, and Afghanistan, while horrible, are quite different. They are not wars of attrition. They are wars of occupation. We have not used the complete power of our military to destroy the infrastructure of these countries—if we did, they would be nuked.
I agree, occupying would be extremely difficult (and inadvisable, and pointless). But if we wanted to obliterate Iran—in response to, for example, Iran shooting a nuclear missile at one of our allies—we could. Iran, unlike the Soviet Union, is completely outmatched in the nuclear arena; any world-war-level provocation on their part would, under the doctrine of MAD, result in their swift and total obliteration. Which is one reason why they aren’t going to provoke World War III.