The Main Core database tracks Americans who are considered potential threats in the event of a national emergency. It was first developed in the 1980s using software called PROMIS, which was designed as a case management system by a private company, Inslaw, for federal prosecutors. It provided the ability to track people within the legal system across multiple databases. The PROMIS software was taken from Inslaw via „trickery, fraud and deceit“ by the Department of Justice and modified by US intelligence agencies to monitor intelligence operations, agents and targets.

The stolen software had users in multiple federal agencies including Lt. Col. Oliver North who created a secret dissident tracking system under the Reagan Administration‘s Continuity of Government program.