Before and during the Civil War, Americans argued a lot about how much power the federal government (like the President and Congress) and state governments should have. Some people believed the federal government should be stronger to make sure there were laws that applied to everyone, especially about slavery. They were worried that if states had too much power, it could lead to unfairness.
On the flip side, many people, especially in the South, believed that states should have more power to make their own choices, including whether or not to allow slavery. They felt the federal government was threatening their rights by trying to set rules they disagreed with.
These disagreements escalated and contributed to the Civil War, as it turned into a major conflict over states' rights versus federal control, with slavery becoming a key moral issue. It was a huge battle over who should be in charge and make important decisions for the country.