Definition of "MAD"

[T]he only bombs anyone dropped—on Hiroshima and Nagasaki—were Uncle Sam's message to non-nuclear Japan. MAD was salvation. MAD was security. MAD was the way of life most of us grew up with, the prevailing logic of uneasy peace. So whatever became of our mad, mad world?

2005 February 7, Peter Preston, “A nuclear Iran is not the problem”, in The Guardian‎

But the American government worries that MAD-style deterrence will no longer work. Terrorists, for example, might not care about the threat of destruction.

2005 February 24, “Muon-assured defence”, in The Economist‎