I am just wondering, but what nation in history used Racial or Ethnic Strife as a form of controlling the population (ie taking People's rights away?)
Well, I guess any regime that exploited ethnic conflict(ie. "You don't like these people? Well, we'll lock 'em up for you!") would qualify. Czarist Russia, Jim Crow USA, South Africa, the list goes on.
Though if you mean they used the strife to control the WHOLE population, not just the unpopular ethnicities, that might be a bit of a rarer bird. Usually in such states, the majority or dominant population are left relatively free to do what they want.