Lincoln went to war to preserve the Union and won. The South went to war to preserve an economic system based on the use of slave labor and lost everything.
The Disaster had been looming for over a decade before Sumter. John C. Calhoun was the intellectual father of secessionist thought.
He went to war to prevent the South from taking over the European trade from his powerful monied allies in New York. He won because the North had five times the population of the South, and could keep killing men in a war of attrition until the South no longer had sufficient men to keep fighting.
A lot of people died just so the power brokers who still run this nation today, could keep their hands on that economic power.
The South went to war to preserve an economic system based on the use of slave labor and lost everything.
Lincoln was going to preserve that too. He made every effort to keep the slave system going, including supporting a constitutional amendment to further protect slavery. Lincoln was okay with slavery when 75-85% of his government was being paid for by slavery. He wanted it destroyed when it became clear his crony capitalist power brokers would no longer be able to control it.
It was all about the money and who was going to control it. Nobody in positions of power gave a sh*t about the actual slaves.