Protecting slavery, Lincoln declared, had become the chief irritant that provoked the Southern states to reach for the solution of disunion. - Allen C. Guelzo

Anyone who sits down for a moment to think about what the alternative would have looked like—a successful breakaway Confederacy—and how that would have flowed downstream has to be with impressed with what Lincoln was able to save us from. There is in the end no intrinsic reason why the Southern Confederacy should not have achieved its independence. And if they had, that would have had serious implications for the later role the North American continent plays in world affairs. Imagine a North American continent as divided politically and economically as South America. This would take the United States off the table as a major world player, and then what would you do with the history of the 20th century?

[T]he very people who write so disparagingly about it either do not understand it, or I suspect even more, understand it all too well and do not like the implications of it.

What if George McClellan had won the presidency in 1864, defeating Lincoln? He would have immediately begun negotiations with the Confederacy. And it is difficult for me to imagine that those negotiations would have not involved some sort of provision for rendition.