[DiogenesLamp]

The self interest, protection of the economic system that evolved in the deep South. nothing more nothing less.

The South never pretended it was about anything other than their own self interest. The North has billed their invasion as a great moral conflict with God on their side.

[Bull Snipe]

The South never pretended it was about anything other than their own self interest

That is correct, it was in best their self interest to leave the Union to ensure that their economic system was not interfered with by the incoming Lincoln/Republican administration.