Unwittingly, what we're addressing here is that old peace-knick question: "Why do we need so many nukes that we could destroy the world 20 times over?".
The answer is/was (once upon a time), that we need to have so many, in so many different places (on subs, on bomber, in silos, in hardened silos, on mobile launchers), that the opposing nuclear power will have *NO* opportunity to think that they *might* have a chance of getting all of ours "on the ground".
That's why we always built more, and never retired the old stuff. Because, if tensions ever rose to the point where we thought they might be ready to roll into Berlin (or vice-versa), touching off WWIII . . . we had to be sure that *they* knew they'd never get enough of our nukes on the ground to avoid a massive/devastating counter-attack.
So, perversely, the most responsible thing to do was to constantly build more nukes. Because. . . imagine the horror if, in a crisis, the Russians thought that *we* were contemplating a launch. . . and therefore decided "Well, we might as well get ours off first and try to take as many of theirs out as we can".
By having so many nukes on so many different delivery platforms, we assured that flawed logic like that would not work. There was no efficacy in trying to "pre-empt" an attack. You just had to hope/pray that the other side wouldn't launch first.
I think Civ3 does a good job of modeling this if they allow ICBMs to survive nuclear attacks. Though, I think it would be cool if there was *some* chance of knocking them out. That would be more realistic.
I read in the FAQ, however, that nuclear deterrance as described above is not factored into the enemy AI. That's a shame. I hope they fix that.
Hurin