Mutually assured destruction (MAD) is the idea that if one of the cold war powers tried to nuke the other, there was a good enough warning system that the defender would be able to launch their nukes as well. ... Because they couldn't attack each other outright they fought through proxy wars and spheres of influence.
mutually assured destruction was an agreed upon course of action that stated if two countries were to get into a nuclear war, a majority of the populations of both the countries would dwindle and utterly destroy both. Because both the U.S. and U.S.S.R. did not want to lose themselves as countries and their populations, the Cold war never had any nuclear action taken, hence the name Cold War.
