Mutually Assured Destruction (MAD) is a military strategy and national security policy that posits if two opposing sides both possess the capability to destroy each other with nuclear weapons, neither will initiate conflict for fear of total annihilation. This concept was central to the Cold War, as it influenced the arms race and shaped the strategies of superpowers like the United States and the Soviet Union. The underlying idea is that the threat of complete destruction serves as a deterrent against nuclear war, creating a tense but stable peace between rival nations.