History of North America

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

Slavery

The issue of slavery was the greatest issue that divided the North and the South prior to the Civil War. The North was largely opposed to slavery, while the South was largely in favor of it. This difference in opinion led to a number of conflicts between the two regions, including the Missouri Compromise of 1820, the Compromise of 1850, and the Kansas-Nebraska Act of 1854. These conflicts ultimately led to the Civil War, which was fought over the issue of slavery.