A lot of apologists for the South claim that the Civil War was not about slavery, but about states’ rights. There is a hint of that in The Birth of a Nation, with the head of the Cameron household expressing alarm that the sovereignty of the individual states is being disregarded by Lincoln’s administration. But the main thrust of this movie is that the mixture of white and black is evil, and that it is the ultimate cause of the war. The very first scene depicts the first Africans being brought to America, which was the first step toward disunion. The suggestion is that it would have been better to leave the Africans in Africa.
But it is too late for that, so the next best thing, according to this movie, is white supremacy and segregation, especially in the form of slavery. This is shown as being a workable solution, for we see how happy the black slaves are, doing a jig for their white masters, whom they adore. The black slaves are depicted as being content with their lot, lucky to be so well cared for. If the mixing of black and white in a general sense is bad, the mixing of black and white in a sexual sense is a great evil. This movie is positively obsessed with the horror of miscegenation. And the mulatto, the offspring of such an evil union, is naturally the embodiment of that evil. Furthermore, the mulatto, being half black, is legally a Negro, and thus his lot is cast with the Negro. But being half white, he has the intelligence and the ambition of a white man, and cannot be satisfied with the black man’s lot. He knows that the only way his position in life can be improved is if the position of blacks in general is improved, if they can become equal to whites, and thus the mulatto becomes a rabble rouser and a sower of discord. The result is that he becomes a traitor to both races.
There are two mulattoes in the movie. The first is Lydia, the housekeeper of Austin Stoneman, a powerful member of the House of Representatives. She is made miserable by the fact that she is almost white, so close to being white that it tears at her soul. She is Stoneman’s mistress, and as such has influence over him, leading us to suspect that she has been instrumental in goading him to help bring about a Civil War to free the slaves and in encouraging him to impose harsh terms on the defeated South at the war’s end.
A second mulatto, Silas Lynch, heads to Piedmont, South Carolina at Stoneman’s request, in order to oversee Reconstruction. When Lynch gets there, he finds the former slaves contentedly continuing to work for their former masters, and even worse, still doing the jig and eating watermelon, so he knows he has his work cut out for him. Soon, Stoneman decides to go to Piedmont for his health, taking his daughter Elsie (Lillian Gish) with him. This suits Lynch just fine, since he has designs on her.
The blacks come to dominate the courts, both as judges and jurors, so that whites are always at a disadvantage, and the blacks win a vast majority of the seats in the state legislature after the election. One of their first acts is to pass a law allowing blacks and whites to marry. In response, Ben Cameron realizes that whites can regain power by forming the Ku Klux Klan.
Meanwhile, Gus, a black captain the in army, has taken a fancy to Ben’s sister Flora (Mae Marsh). He follows her into the woods and begins making advances. She runs to the top of a steep cliff, and when Gus refuses to stay away, she leaps to her death, thereby saving her honor.
Now it is war. But it is not simply black against white, for many blacks are depicted as loyal to their former masters. Nor is the wartime animosity between North and South of significance compared to the all-important cause of protecting white women from black lust. When a bunch of mostly Southern whites take refuge in a small house where Yankee veterans live, the intertitle says the former enemies are united in defense of their “Aryan birthright.”
Lynch wants to marry Elsie. He says he will preside over a black empire, with her as his queen, but she is horrified. So, he locks her up and prepares for a forced marriage. But then Stoneman, who was temporarily away, returns. When Lynch tells Stoneman that he wants to marry a white woman, Stoneman congratulates him, for he thinks that is a great idea. But when Stoneman finds out it is his daughter Elsie that Lynch wants to marry, he is outraged. The hypocrisy is simplistic and ridiculous.
Meanwhile, back at the house where the Yankees have taken in the Southern whites, the blacks have surrounded the house, trying to break in. When the people inside the house run out of bullets, the men prepare to bash the brains out of two women and a little girl rather than have them suffer a fate worse than death. At the last minute, the Ku Klux Klan rides to the rescue.
In the end, the Klan is victorious, disarming the blacks and disenfranchising them on election day. White rule has been reestablished, and all is well.