Several incidents of racism in the film indicate that, at least originally, many in the North were not fighting the war in support of justice for blacks. Lincoln's Second Inaugural tells us that the goals of the war had changed by 1864. What was the change and why did that change come about?

According to Lincoln's second inaugural speech, the reasons for the war ceased to be about the cause of slaves and became about the need for each part of the country to want to triumph over the other. This happened because the quarrel took longer and took a larger proportion than expected.

Explanation:

Lincoln states that the war was started using slaves and their liberation as the main attraction and reason for such a devastating conflict to start. However, everyone believed that the war would be quick, but it took on too great proportions, took too long. During that time, the cause of the slaves could have been resolved quickly, but the war became a dispute of strength and power between the two parts of the country. The war continued with the objective of one party showing itself triumphant over the other, showing its power and its capacity to dominate.