Colossus

Charles Forbin has dedicated the last 10 years of his life to the construction of his own supercomputer, Colossus, rejecting romantic and social endeavours in order to create the United States' very first Artificially Intelligent defence system.
Colossus is a supercomputer capable of taking in and analysing data rapidly, allowing it to make real-time decisions about the nation's defence.
But Colossus soon exceeds even Forbin's calculated expectations, learning to think independently of the Colossus Programming Office, processing data over 100 times faster than Forbin and his team had originally anticipated.
The President hands off full control of the nation's missiles and other defence protocols to Colossus and makes the announcement to the world that he has ensured peace.
However, the USSR quickly announces that it too has a supercomputer, Guardian, with capabilities similar to that of Colossus.
Forbin is concerned when Colossus asks - asks - to communicate with Guardian.
The computer he built shouldn't be able to ask at all.