The Birth of a Nation is quite often said that it restarted the KKK as a movement. I assume the KKK was an integral part to initiating the Great Migration, but to what extent did the release of a single movie have upon the great migration? Is it possible to state that Birth of a Nation is the movie with the largest effect upon history?
The southern exodus had far more to do with the interruption of European immigration through war and the rival blockades that took hold in 1915: arrivals fell from over 5.1 million in the five years to June 1914 to fewer than 1.2m in the next half-decade, while industry surged in response to wartime demand. Whites left the South in similar numbers to their black neighbors, drawn by opportunity as well as fleeing its absence. Mr Griffith was overtaken by vast impersonal forces.