Every one, according to Christian thought, has certain Inalienable Rights. When one group infringes on those rights, Trouble in River City. When one group gets in power and favors ones from their own group over others, anger brews. When the last straw, so to speak, breaks, the score gets evened. Because the anger has usually been suppressed for so long, when they get the chance finally, they overreact and kill all of that group that they can find. Rwanda, Shiites v Sunni's, Hatfields and the McCoys, Vietnamese Communists v the in power elite. The 'final' authority is in the hands of the 'people'.