I do not know what current day nuclear weapons doctrine is (maybe Justin Kelly can chime in on this one). During the Cold War, all WMDs were considered to be of one class. If our forces in Europe were attacked by the Warsaw Pact with gas, germs or nukes then the standing doctrine was to respond immediately with tactical nuclear weapons. There was a rational behind this doctine in Europe. The Warsaw Pact had a huge numerical advantage in conventional weapons, typically 4:1. In war gaming, if an attacker has a 4:1 advantage then victory is virtually assured. Also extensive aggitation-and-propaganda over several decades had effectively demoralized the West German population to collapse like a house of cards if there had been an attack. Of course the Soviets never did launch an attack because NATO was armed to the teeth with nukes and clearly intended to use them. The enormous cost of maintaining this huge standing army was one of the main reasons why the Soviet Empire imploded. It's almost funny that the Soviet's were such clever military tacticians but failed to notice that they were running out of money. Anyway, I don't know what our current nuclear weapons doctrine is (we might not have one). Certainly Mutual Assured Destruction won't work against an Islamic fanatic who thinks he's going to heaven.

Gary