What motivated so many Americans to fight and kill one another in the long and bloody American Civil War? What did they believe they were fighting for? Solution There were several reasons for the civil war: 1. Abolition of slavery - The people in the south were mostly plantation farm owners which is a labour intensive work. So, when Abrahim Lincoln decided to abolish slavery, it was seen as a direct attack on their way of life. They did not want to be dictated terms by the people from the north who were mostly business owners and the northerners did not support slavery. 2. Union over State powers - In the decision to create policies such as abolition of slavery, the states had no individual power to decide if it supported or opposed the idea. This made the southern states feel threatened by the power of the union over them which they were not accustomed to prior to 1789. 3. Denial of request of secession - Some states in the south wanted to secede from the United States but the then president Abrahim Lincoln refused to entertain this idea. This riled up the people in the south even further. The Northerners believed to be fighting for the abolition of slavery as well as uniting the nation under a single rule of the union. On the other hand, the southerners believed to be fighting for their way of life and seceding from the rest of the United States..