Six false alarms occurred at NORAD in 1978, 1979, and 1980. These false alarms subsequently regenerated interest in launch policies and the increased possibility of accidental nuclear war, which motivated this investigation. We construct a new model to address several questions: What is the sequence of events and reasonable timing between events in the missile warning system? How much time do decision makers have to respond to a threat? What effects do United States launch policies have on decision-making time? How likely is accidental nuclear war? The results show that accidental nuclear war is not very probable with launch-under-attack, but significantly more likely if the Unite States adopts a launch-on-warning policy. The final decision and responsibility to use these policies, once they are implemented, rests entirely with the President of the United States. Keywords: Ballistic missile early warning system; Early warning system. (Theses).