"The tools of conquest do not necessarily come with bombs and explosions and fallout. There are weapons that are simply thoughts, attitudes, prejudices -- to be found only in the minds of men. For the record, prejudices can kill and suspicion can destroy, and a thoughtless, frightened search for a scapegoat has a fallout all its own -- for the children, and the children yet unborn. And the pity of it is that these things cannot be confined to the Twilight Zone."
The Monsters Are Due On Maple Street (one of the first-season episodes CBS does not offer on the Net)