The Southerners of the 1830s, 40s, and 50s watched in horror as the North was transformed by an industrial revolution fostered by the liberty of "free labor," with rapidly spreading prosperity and a population that was swelling from falling death rates and massive influxes of immigrants, while everywhere in the South society languished in medieval poverty. They realized their system was doomed. In one more generation, the North would out-vote them on every national question, and—if the votes weren't counted—would outnumber them and outshoot them on the battlefield. Their response was aggression. To balance the votes they were sure to lose in the House and for the presidency, Southerners belligerently demanded that slavery be extended to all of the territories (from California to Minnesota), and they threatened to beat or murder anyone who spoke out against their cause. Finally, seeing that their social system was inexorably losing in lawful political competition, they bet everything and rolled the dice on secession and war.
The left's journolists pre-planned ambush was nothing like the South of the 19th century. The South's society that believed in a strong state government and a weak Federal Government was much in keeping with the founders.
There was some poverty then (by todays standards) in both North & South. There was also industry in the South, but it was largely agricultural (& not all based on slavery). Protective tariffs on imported manufactured goods (benefitting the new Northern manufacturing) were countered by foreign nations by "tariffs" on American agricultural goods. This did divide the nation long before the conflict.