Quote by Edward Bernays:
“The conscious and intelligent manipulation of the organized habits and opinions of the masses is an important element in democratic society. Those who manipulate this unseen mechanism of society constitute an invisible government which is the true ruling power of our country. ...We are governed, our minds are molded, our tastes formed, our ideas suggested, largely by men we have never heard of. This is a logical result of the way in which our democratic society is organized.
Vast numbers of human beings must cooperate in this manner if they are to live together as a smoothly functioning society. ...In almost every act of our daily lives, whether in the sphere of politics or business, in our social conduct or our ethical thinking, we are dominated by the relatively small number of persons...who understand the mental processes and social patterns of the masses. It is they who pull the wires which control the public mind.” ref
The Art of Divide and Conquer
Groups whose belief structures clash, tend to revert to more destructive means in their attempt to defeat those they perceive as a threat. A society dominated by such groups is thus divided in increasingly hostile conflict and as a result not does the population as a whole become weakened, but its eyes are diverted away from the actions of those operating behind the scenes.