mutual assured destruction

Mutually assured destruction or mutual assured destruction (MAD) is a doctrine of military strategy and national security policy which posits that a full-scale use of nuclear weapons by an attacker on a nuclear-armed defender with second-strike capabilities would result in the complete annihilation of both the attacker and the defender. It is based on the theory of rational deterrence, which holds that the threat of using strong weapons against the enemy prevents the enemy's use of those same weapons. The strategy is a form of Nash equilibrium in which, once armed, neither side has any incentive to initiate a conflict or to disarm.

The result may be a nuclear peace, in which the presence of nuclear weapons decreases the risk of crisis escalation, since parties will seek to avoid situations that could lead to the use of nuclear weapons. Proponents of nuclear peace theory therefore believe that controlled nuclear proliferation may be beneficial for global stability. Critics argue that nuclear proliferation increases the chance of nuclear war through either deliberate or inadvertent use of nuclear weapons, as well as the likelihood of nuclear material falling into the hands of violent non-state actors.