While in the US two weeks ago I had the chance to buy a print issue of Wired with the article Inside the Apocalyptic Soviet Doomsday Machine. Whether you believe everything or not doesn’t make this a less interesting read:
The point of the system […] was to guarantee an automatic Soviet response to an American nuclear strike. Even if the US crippled the USSR with a surprise attack, the Soviets could still hit back. […] Dead Hand is continuously being upgraded.