The author is certainly right about the proximate cause of the Civil War, it was about slavery. Reading the words of those states that seceded make that point clear. But, the paragraph above reveals a complete lack of understanding about the eventual fate of the hideous practice. Slavery was gone in the Western Hemisphere and in European societies by the end of the 19th Century. It endures today in Africa and Muslim societies
Economics plays a large role in that fact. Industrialization is a major reason why. As manufacturing and mechanized agriculture began to gain sway, the economic foundation for slavery waned. While the cotton gin was probably an example that demonstrated the opposite effect, over time advances in industrial society would have produced cheaper methods of producing cotton than was possible with slave labor. Slaves were very expensive, and became much more so in the waning years. The Royal Navy had put a halt to the Atlantic Slave trade, so new slaves were only available through natural increase. That wasn't enough and prices as shown in bills of sale, estate papers, and wills reflect the supply and demand problem. With so much wealth tied up in slave labor, the South was not about to freely relinquish their fortunes. Look at what happened in Wisconsin when the Governor tried to get state employees to pay for part of their health. People get very worked up when their family fortune comes under threat.
And the Revolutionary war of 1776 was about tea.
-- A Linclon, destroyer of republics.