Colossus: The Forbin Project

The U.S. has handed over control of its nuclear defense system to the Colossus supercomputer designed by scientist Dr. Charles Forbin. It soon becomes clear, that the now-sentient Colossus is far more intelligent than its creator realized—with the fate of the world hanging in the balance.
This is the dawning of the Age of Colossus (where peace is compulsory... freedom is forbidden... and Man's greatest invention could be Man's greatest mistake).