Final answer:
Mutually Assured Destruction (MAD) is a theory of nuclear deterrence that states that no nuclear power would attack another nuclear power, as any such attack would lead to the launch of enough nuclear weapons to destroy both nations.
Step-by-step explanation:
Mutually Assured Destruction (MAD) is a theory of nuclear deterrence that states that no nuclear power would attack another nuclear power because any such attack would lead to the launch of enough nuclear weapons to destroy both nations. The idea behind MAD is that if both sides possess the ability to destroy each other and are committed to launching these weapons in the case of an attack, neither side will attack the other due to the likely consequence of mutual annihilation.