Indeed.
At that time deterence has failed, so what is the POINT.
I have a high belief though that deterence wouldn't fail, so we'd never get to that position.
So you are narrowing it down to a massive ICBM launch ?
Incidently, where is the option :
"I wouldn't have to because the very fact I have the weapons and have a stated intention to possibly use them, would deter any situation occuring where the question would be asked in practice"
It would depend on the situation would it not ? With strategic nukes, if it got to that situation it would mean there was already at least 1 incoming ICBM.
Would there be a different response to 1 incoming ICBM, or to 100s ?
Would there be any merit in at least nuking the attacker's remaining...