IDonT said:
US has enough Nukes to wipe out the planet many times over. Nuking every square inch of China is not a question of if the US could, but if the US should in light of the consequences.
Just looking at the US SSBN fleet and you will see the amount of nuke power the US possess.
US has 14 remaining Ohio class nukes, each armed with 24 trident missiles, each carrying 12 MIRV warheads with a yield of up to 700 kilo tons.
This is silly. You should download Google Earth and start looking at the sheer scale of the countries you are talking about.
The only way to "nuke every square inch of China" is by radiation and fall-out. The actual blast radius -- and 700 kiloton yield nukes are small -- isn't that big.
For example, a one megaton bomb in manhattan would destroy all of manhattan, and probably 50% of brooklyn and have little direct effect once you are some distance away from the coast in New Jersey. All the nuclear weapons of the US can't completely nuke an area the same of the appalachians for instance, probably not even 25%.
Nukes are most useful against highly urbanized countries. Back in the 70's, when China was not urbanized, nuking cities will not cripple the country.
Besides, Chinese cities all have bomb shelters, and American cities don't. So the American population are the ones really concentrated and exposed.
Fall out and nuclear winter is the real wild card. Who really knows how far fall out will travel and what would happen in a nuclear winter? It is likely that the Himalayan mountains are the safest place to be in a nuclear winter because you will be above cloud cover.