This is a very old thought. Both LBJ and MLK understood this, at least in the context of racism as a tool to divide the lower and middle classes of society. You've probably heard this quote, attributed to LBJ:
> If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you.