- Both sides had the capacity to destroy the other completely
- Both sides ultimately wished to survive
- Neither side could preemptively strike the other without assured and complete retaliation
- Therefore, neither side would initiate nuclear war
MAD was both reviled and praised during the Cold War. Game theorists spent much time debating various changes in policy and their effect on MAD. In the academic formulation, when MAD is in effect, cooperation became a dominant strategy in the prisoner's dilemma so long as defection would not lead to any discernible benefit.
As a general rule, a 400 megaton supply of nuclear warheads is sufficient to assure the destruction of large nation, so in calculating nuclear stockpiles to determine if MAD exists, the goal is to see if you can eliminate the opposition's stockpile in a first strike to below 400 megatons. If you can, then, in the grim calculus of nuclear war, first strike becomes an option.
Stability vs. Instability
Alterations in the basic premises of MAD had the potential to destabilize the balance between the US and USSR, possibly igniting nuclear conflict. Therefore, much time and energy went into debating even small changes in policy.
Anti-Ballistic Missile Treaty
Anti-Ballistic Missile systems (ABMs) are weapons systems designed to intercept and destroy incoming weapons systems, usually Inter-Continental Ballistic Missiles (ICBMs). Since this could theoretically prevent a fatal retaliatory strike from an opponent, ABMs are considered inherently destabilizing. The period between the beginning of the development of such a system and the point at which it becomes operational represents a closing window for an adversary's first strike. This fact lead to the ABM treaty, which allowed both sides limited deployment of ABM systems. Current American governmental policy sees this treaty as having become irrelevant with the demise of the USSR.
Strategic Defense Initiative
The Strategic Defense Initiative (SDI), which began development under the Reagan administration, was thought by some groups, especially the Union of Concerned Scientists, to represent a destabilization of MAD. The reasoning behind this was essentially the same as that of the ABM dilemma above.
First Strike Capabilities
"First Strike" systems are those which either preserve a fatal second strike component, or entail independent & undetectable first strike systems. "SLBMs"', or submarine-launched ballistic missiles, are one type of first strike system employed heavily by the United States. The USSR, in the Cold War, employed "RLBMs", or rail-mounted ballistic missiles, which is to say that the USSR would use their massive railway system to furtively move and conceal a potent first strike or deterrent system.
The cultural influences of MAD were pervasive, down to the acronym itself.