Hi,
For many years, people have argued over the divide of the U.S, the North, and the South. The North is the best place for African Americans, although it wasn't all that good, it was much better than the South in which many African Americans were taken into slavery and were treated as objects and not humans. When Dred Scott was moved from a slave state into a non-slave state, many people believed that this movement should have at least granted him freedom. But when the U.S denied his freedom and said that he was still considered a slave under authority, the conflict started to arise. People from all over thought this was absolutely outrageous, a young man denied his freedom in a non-slave state.
I hope this helps!