The Civil War ultimately centered around the significant struggle between states' rights and federal authority, particularly regarding slavery. Southern states advocated for the autonomy to determine their own laws, including the continuation of slavery. Conversely, the Northern states, led by the federal government, sought to preserve the Union and end slavery. This conflict over the balance of power between state and national governance sparked intense debates and ultimately led to a violent war. The war concluded with a focus on national unity and the abolition of slavery, reshaping American society.