Like shit, probably.
Alright, this isn't just gonna be a SHITpost. Let's take a deep look into this.
Alright, it would literally look like shit, but first we have to understand what shit looks like. So, what we're looking at is a USA that just lost its most major source of cotton to fuel their factories: the South. This unquestionably results in a catastrophic economic depression in the North, and due to the absence of tariffs (most likely, since they hated tariffs) in the South, quite possibly an economic boom down there in contrast. Not trying to go Turtledovey here, but the South would be besties with Britain and France until they tell the South to get rid of slavery; they either continue being friends if the South drops slavery, or they drop the South for the North if they refuse to let it go, and the South likely turns to a new ally: Germany.
This is just the gist of it: North is fucked, South is doing great.