Franklin Pierce considered letting the South go, but this was impossible: not only was there then a problem of the vast amount of Federal property within the Southern states, but dividing the vast western territories- the South was agrarian and wanted land to expand its economy, was not going to be content within its borders. Lincoln also pointed out the crux of the problem with secession. Allow a region to split off because it didn't like how the majority had voted, and it wouldn't stop: Pike County might split from Georgia, Molena might split from Pike County.

With Secession impossible, the great difficulty with bringing the South back into the Union was the situation after the 1857 Dredd Scott decision. Before Dredd Scott, there had been constant legislative compromises , constant negotiation and balancing between the factions in Congress, because there were essentially two conflicting sets of laws within the US and so a constant dispute. In the North, there weren't slavery and slave codes, in the South there were. Dredd Scott clumsily made them consistent, set down that a slave was a slave throughout the US. This was intolerable to the North. With the Fugitive Slave Act of 1850, Northerners had been legally obligated to help catch escaped slaves and return them to their owners, just as if they were stolen property, but in effect some northern states had been able to make that unenforceable. The Dredd Scott decision allowed legal challenges to that, such as Ableman vs Booth in 1859, so that state legislatures and courts in the North were in the future going to have to fall in line with the Act. Dredd Scott decreeing a a slave was a slave anywhere in the US also opened the door for slavery extending into the new western territories, or possibly anywhere. It raised Southern expectations, encouraged the Fire Eaters, the slavery advocates in Congress, to think that they had completely won, that all the compromises of the past were over. It very much set the country on the path to the Civil War.

There were plenty of people in the North before the War who didn't want to fight over slavery, just as there were plenty after the War who didn't want to go to great lengths, use armed force, to protect the rights of the freedmen: and in the end they abandoned Reconstruction. But slavery had been a huge, intractable legal problem for much of the preceding decades, occupying the best and most astute politicians of the country, and Dredd Scott, whether those Northerners liked it or not, made any more compromise impossible, made it impossible to avoid the question: slavery had to exist everywhere, or not exist everywhere: the most inconvenient of inconvenient truths.