What was the key causes of the Civil War to start?

The economics of slavery and political control of that system that was central to the conflict. A key issue was states' rights.

Explanation:

Economic interests, cultural values, the power of the federal government to control the states, and, most importantly, slavery in American society

A common explanation is that the Civil War was fought over the moral issue of slavery. In fact, it was the economics of slavery and political control of that system that was central to the conflict.

A key issue was states' rights.