Carolyn, I never say slavery was not an issue. To say so would be preposterous. But, here is where it gets technical. The North had been prying into the South's business trying to abolish slavery, create a central banking system, force wage labor on the Southerners. At every turn the Yankee was trying to make Southerners like them. They had blocked and parried every stab at the Southerners way of life until Lincoln was elected. They knew that the Radical Republicans had the strength to over power them.

The War for Southern Indepence is so complex no one can pin point one specific cause. I think David said it best
One State seceded over slavery, five States seceded over the right to secede and seven States seceded because the Northern President attacked the other six. No one else has so correcetly simplified the cause of the War better than that.