Sorry if I'm naive but what is M.A.D. ?
Mutual assured destruction (MAD) is the doctrine of a situation in which any use of nuclear weapons by either of two opposing sides would result in the destruction of both the attacker and the defender. The doctrine assumes that each side has enough weaponry to destroy the other side and that either side, if attacked for any reason by the other, would retaliate with equal or greater force. The expected result is that the battle would escalate to the point where each side brought about the other's total and assured destruction - and, potentially, those of allies as well.

Assuming that neither side would be so irrational as to risk its own destruction, neither side would dare to launch a first strike as the other would launch on warning (also called fail deadly). The payoff of this doctrine was expected to be tense but stable peace.
http://www.wikipedia.org/wiki/Mutual...ed_destruction