IMHO, the risk of nuclear war is higher than we think. Can you imagine the number of expected casualties of all-out-war with China? We've played this game before. Japan/WW2. The US _will_ nuke China and justify it under number of lives saved.
Japan didn't have a nuclear second-strike capability with the range to hit the US. (Or, literally, any part of that taken independently.)
The US leadership can't even make a remotely plausible argument, after emerging from their bunkers after the exchange is done, to have “saved lives” by nuking China.