So I bring up this thought experiment once again: what is the point of actually (note the word) launching a retaliatory strike if your country gets hit by nukes? The entire point of having nuclear deterrence is to deter the enemy from launching in the first place. If this primary function has failed, then why is there a point of actually launching a retaliatory strike that will only lessen humanity's chance of survival?
Sure, China will be destroyed and the US (or any other country) will survive, but destroying the other country won't bring China back. It's a horrible thought experiment but a question nonetheless. The nuclear arsenals of these countries exist purely as a psychological deterrent.
Nukes aren't as powerful as people commonly imagine. Sure they can wipe out cities, but it wouldn't be an end of the world event by any means. MAD doctrine is that of in the context of modern civilization, nukes can be civilization destroyers. It can destabilize and destroy the fabric of nations etc but there aren't enough nukes to destroy all life on earth.
Nuclear power reaches point of diminishing returns:
Therefore it would be in the best interest of China to reach nuclear deterrence parity with that of the US.
Now when people say "long term", scope is important. In the very long term all matter decay back into radiation and nothing will exists in the universe anymore and even time and space will someday lose distinction. A billion years from now the sun will go red giant and as it burns out fuel, making it so large it will swallow the earth itself.
So how long is the appropriate context of long term then? China has recorded history of 5,000 years or more. If we are to say "long term" means another 5,000 years, then does it matter what happens in the next 5 or even 50?
If we define 5,000 years as "long term" then what happened the last 100 years and the Chinese Century of Humiliation was merely an aberration and in the long term China strives to regain its preeminence.
So lets say US does a surprise first strike of China using nuclear weapons taking out the CCP in one blow and basically decapitating all C&C. My only concern is the remaining military commanders in the position to retailate against the enemy would or could be too pacifist and won't actually follow through to completion... nevermind the technical hurdles and other contingencies.
But to me it isn't about "revenge" per se, MAD does not mean all life on earth get destroyed, just all modern civilization. Animals will still do great...
MAD is actually about leveling the playing field and using nukes as the "great equalizer" so that what is left of modern civilization can then start over and rebuild. If US nukes China and China decides not to retailate then that will mean America will secure the next ten centuries or possibly forever. The first nation to truly master AI and time travel or other exotic tech will stay on top forever....
MAD is really about leveling the playing field with nukes as the 'great equalizer' in this ultimate scorthed earth policy, and therein is the deterrence, that even if China is completely nuked it can still effectively bring US civilization back to zero and then whats left of both nations can rebuild from scratch... I don't see how nukes can ever wipe out humanity as a species, but it can be the ultimate reset of nations and civilizations. If China was attacked in such a manner and choose not to retailate then that would be like willingly giving the future to the Americans yet again. So in this regard I believe nuclear parity is very important, China should and must catch up to the US quantitatively and qualitatively and spare no expense to nation guard.