The Post Attack Command and Control System (PACCS) was a network of communication sites (both ground and airborne) for use before, during and after a nuclear attack on the United States. PACCS was designed to ensure that National Command Authority would retain exclusive and complete control over US nuclear weapons. Among other components, it included Strategic Air Command assets such as the Looking Glass aircraft and mission, and various hardened command and control facilities.[1]
The belief by the Soviet Union in the reliability of PACCS was a crucial component of the US mutual assured destruction doctrine, ensuring a long-term stalemate.