Force Asymmetry
Maniakes,
You quote one of my favorite lines from Dr. Strangelove! +1 to you!
Seriously though, the problem with that analysis is that it overlooks the differences in both the forces available to each side, and the way that they were deployed. The Soviets were an ICBM heavy force (the lack of good ports and the plethora of isolated wasteland was a big factor in this, along with the technical problems in building worthwhile SLBMs) where only about 20% of their total warhead count was on SLBMs, even by the end of the Cold War. This means that they were far, far less likely to be willing to 'ride out' any sort of first strike, and far more likely to adopt measures to shorten the decision cycle, thus rendering even a decapitating strike valueless.
More to the point, their subs were deployed very differently than ours. First, most were tied up at port most of the time, which means that they were potentially vulnerable to a first strike. Those that were NOT, however, were in 'bastions', localized geographic areas, protected by minefields, attack subs, and surface vessels. This is very, very different from our own sub patrols, where were individual subs hiding in the oceans. Soviet SLBMs, even at the end of the Cold War had terrible guidance systems, with CEPs of well over 400-500 meters in many cases, which meant that they were almost exclusively used for countervalue targets. These missiles carried reasonably large (500 kt to 1Mt class) warheads, and thus didn't need accuracy to take out their large, soft targets. Soviet planning presumed that these bastion subs would have the ability to provide a survivable second strike against even the most successful American first strike, and that most NATO ASW efforts (designed for open-ocean protection of their own naval assets, not hunting SSBNs in protected waters) would be largely valueless. Note that our own assessments tended to agree with this...
So the result would not be the 20 vs 150, it would be 100 vs 150, with far more dirty desparation measures thrown in for good measure. By the way, you will have to take my word for it, but we absolutely DID know about Dead Hand (not as such) certainly from the mid 70s onwards. Even if you don't want to take my word for it (and to be honest, I wouldn't take offense, lots of bullshitters here...sigh), it was hardly an unknown bit of speculation among various targeteers. Both Kissinger and Kahn discussed the idea openly in the early 1960s (this is where the basis for much of Dr. Strangelove and Fail-Safe came from, by the way), and there was nothing magical or even particularly complicated about the approach that was used.
Asnys,
Given the relative force distributions of each side (and please see my note above to Maniakes), the decapitating strike would not significantly degrade any potential Soviet second strike capability, and might in fact accidentally enhance it, as the Soviets threw in whatever desparation, 'last ditch' nastiness that they had available in such a situation. Remember, once you shoot out the only people able to stay 'Stop', the entire system is going to empty itself against you, with no concerns about tactics, reserves, or limitations. The presumption would be that there won't be anything or anyone to care. If that sounds inhuman, remember that the people on both sides thought long and hard about making it as terrifying as possible, and providing as much certainty regarding its use as possible as well.
Ironically, as missile CEPs went down, it slowly became (remotely) possible to fight a limited (i.e. counterforce) war without total wargasm. Granted, the scenarios are somewhat specialized, but the notion that once the first nuke was used everything would go simply was not in the cards. But for any of this to happen, it was vital that the chain of command NOT be too badly disrupted, and both sides went out fo their way to ensure that would be the case. Ironically, when I lived in DC in the 80s, I had the somewhat odd comfort of being in one of the safest places in the US. The dangerous place was St. Louis (I leave the answer as to why this is the case as a puzzle for the intelligent reader....)
Clipper747,
A minor quibble...most of the military bases that the Soviets cared about were ICBMs and SAC airfields, and very few (not NONE, but FEW) of these were anywhere near major population centers. Fallout was another matter, but the limited cases we are talking about would not create so many casualties as to 'force the hand' of the attacked party. Your point about cities being 'held hostage' is most insightful, as is your comment regarding the drawback of decapitation.