Open-ended topic but an interesting one. If the US had lost the civil war and been forced to let the southern states go, how would race relations in the North have developed differently?
1. Would blacks be seen as having "caused the war" and thus face increased racism/persecution?
2. Would the USA define itself against the CSA and adopt a more liberal attitude towards race relations than OTL?
3. The CSA would probably (at least nominally) abolish slavery at some point, but until then, what actions would the US government take with respect to aiding runaway Confederate slaves (not to mention the question of slavery in the border states)?
FU!!!!!!! So nice to see you my friend. You have been missed. Leave it to you to throw a hand grenade in a room and walk away.
My only question before I answer is whether or not this falls into a hypothetical alternate history thread that will be locked?
Say Atlanta does not fall because its commander is not foolish enough to leave his strong fortifications and engage Sherman in a battle of maneouvre, and Lincoln loses to McClellan in 1864. McClellan will push forward his Peace Plank, try for reunification, will waffle and waver, but under no circumstance will he lose any more troops and will refuse to prosecute the war at the cost of further life and will settle for peace.
You have an end to the War of the Rebellion. The story will read that Lincoln lost because he failed to 'Preserve the Union' by politicizing Abolition with the Emancipation Proclamation. Lincoln divided his own house.
The Thirteenth, Fourteenth, and Fifteenth Amendments will not be passed as written. Dred Scott is still on the books.
Your entire point now revolves around the Border States, including Missouri, which I have no doubt is the basis of your entire line of questioning.
Slavery will be present in both the USA and the CSA as determined by the individual states. Will the Federal Army be forced to occupy the Border States to prevent them leaving the Union? Would anyone DARE to free their slaves in this environment?
Regardless, the slaves would be freed over time. I would have picked a different ending to the War of the Rebellion; but I have never suggested an independent CSA and USA would be beneficial for anyone.