> I'm sure it's been written about a hundred times -- is
> there a generally excepted consensus about the origin
> of the white supremacy ideology?
It arguably arose in seventeenth-century Virginia. Please see the following two essays for introductory information:
The Invention of the Color Line: 1691 http://backintyme.com/essays/?p=12
Why Did Virginia's Rulers Invent a Color Line? http://backintyme.com/essays/?p=22