What is the greatest issue that divided north and south piror to the civil war?

The greatest issue that divided the North and South prior to the Civil War was slavery. The Southern economy relied heavily on slave labor for its agricultural production, particularly in cotton, while the Northern states were increasingly moving towards industrialization and many were advocating for abolition. This fundamental disagreement over the morality and economic necessity of slavery created deep political, social, and cultural rifts between the two regions, ultimately leading to the conflict. Additionally, issues like states' rights and territorial expansion further intensified these divisions.