How did the issue of slavery divide the union?

Slavery had been a divisive issue in the United States well before the Civil War. While the Founding Fathers were debating the exact Wording of the Declaration of Independence, there was a debate to include the Word slavery or not in the document. The idea was that the Colonies were being held as slaves to the crown, but the paradox was that if they were going to state that, how could they in good consciousness keep African slaves as well?

After the Revolution, there was great power struggles in Congress to address slavery. During the early 1800s, the Slave Trade was banned by the British, and internal slave trade began in the United States. This meant that there was trading of slaves between slaves, and Congress had to act to protect the rights of interstate commerce, even if it meant dealing with human lives. Also, there was a struggle to keep the balance of power between the quickly industrializing North and the mostly agrarian South. Whenever a slave state was brought into the Union, a free state would have to be as well. A compromise had been given in 1820 stated that any state below the bottom of Missouri would be a slave state while any above (except Missouri) would be a free state. This would determine the status of the West and slavery.

In 1850, a new compromise was reached in Congress to allow territories that were to become states would have the freedom to choose if they were going to be Free or Slave. A struggle to determine if Kansas would become a slave or free state came to a boil. Many from both sides flooded the state before the vote was to happen, and fighting broke out. During the next few years, battles between pro-slavery and pro-freedom factions broke out, causing the area to be known as Bleeding Kansas.

The final act in leading up to the Civil War was the Republican party's official stance as being pro-Freedom. With the election of Lincoln, many in the South thought that Lincoln would ban slavery (something that he did not do until it became a political necessity) in the South.