I was almost ready to endorse Leonard Greene's suggestion (Letters, New York Times, April 21 2006, page A22) of a "Mutually Assured Destruction" Pact to deter a nuclear first strike until its major flaw struck me.
As far as I know, the only nation considering a pre-emptive nuclear strike at present is the United States. I really cannot see countries like Britain, France, India, and Pakistan or Israel (if it has them) or Russia and China unleashing nuclear missiles on Boston, Los Angeles, New York and Washington.
It is just not plausible. So MAD may work for deterring small states but not for deterring the US.