Fox News has, sadly, become the purveyor of a 50-state "Southern strategy," the plan perfected by Richard Nixon to use race to scare Southern Democrats into becoming Republicans by insisting the other party wasn't merely trying to fight racism, but give blacks advantages over whites (Fox News boss Roger Ailes, of course, famously worked for Nixon). Now Fox is using the election of our first black president to scare (mainly older) white people in all 50 states that, again, the Democratic Party is run by corrupt black people trying to give blacks advantages over whites (MSNBC's Rachel Maddow laid out this history last week).
Fox News is basically the worst parts of Birth of a Nation presented in real time news form. Portray blacks as scary (or sometimes lazy and shiftless) monsters who only want to cheat and rape and disenfranchise white people. This touches a nerve among white viewers who are predisposed to believe these myths about African Americans, and so Fox News and the tea party creates a feedback loop of mutual fear and support.
Adding... "The helpless white minority."
Birth of a Nation was part of an early form of the Southern Strategy -- it was propaganda in a larger national effort to unify the north and the south around a common enemy. In order to erase the ongoing resentment of the south, a mutual enemy of the north and the south was created: black people. Birth of a Nation helped to unite northern and southern whites around this common enemy by portraying blacks as sinister, lazy, vengeful, criminals who hate whites.