Mutual Assured Destruction(MAD) was an idea during the Cold War that was if one side attacks another than in will basically be attacking itself. MAD was the idea that if one side bombed the other, then it would be like a suicide bombing because if the Soviet Union decided to bomb the United States then we would have been able to bomb them, just destroying the world.  Many people feared this, and they really believed that we could destroy the world. Many citizens believed that by threatening to destroy another country, the United States was putting US citizens on the line.  The idea of MAD is mainly the thought that if one side shoots first, it will be shot down second, and during the 1950s, many people believed this would destroy our world.