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In the antebellum South, the way for an aggressive young man to 'make his fortune' was to get a piece of land, buy a slave, build a house and plant cotton. Cheap or free land was available to the west, so the biggest single expense was that first slave.
The prospect that one could not go further west and establish one's self in the new territories in this manner severely restricted upward mobility. Further, the fire-eaters whipped up a fear that somehow slavery- the biggest single asset of a planter- would be taken away. Added to this was a fear of what freed slaves might do to their former owners and their families.
All of this made slavery far and away the single root cause of the rebellion.
The only 'state's rights' Southerners were interested in was the right to own slaves.
I suggest reading the Confederate Constitution and the various secession ordinances- all of which make it clear that continuing to own slaves was the primary concern.
Also, I suggest reading the letters ordinary soldiers sent family or hometown newspapers. See Chandra Manning, What This Cruel War Was Over: Soldiers, Slavery, and the Civil War. (New York: Alfred A. Knopf, 2007).