Mutual Assured Destruction (MAD)

 "The only winning move ... is not to play (the game)..."

Having discovered the concept of mutual assured destruction ("WINNER: NONE"), the computer tells Falken it has concluded that nuclear war is "a strange game" in which "the only winning move is not to play." WOPR relinquishes control of NORAD and the missiles and offers to play "a nice game of chess".  ~WarGames (1983)  

*Particularly remember coming out of the theater for that one into a sunny day, ... and a new world.  You know how some movies can do that, when you are impressionable?

Stephen Falken : The whole point was to find a way to practice nuclear war without destroying ourselves. To get the computers to learn from mistakes we couldn't afford to make.