There was nothing stopping them from settling the west. Tens of thousands of Southerners settled in the west. The pampered slave owners just couldn't take their slaves with them if they wanted to keep them chattel. I guess the poor little spoiled babies were afraid they would break a fingernail of something if they did any manual labor like the rest of the pioneers and settlers.
So Lincoln didn't have a problem with the idea of "second-class citizenship" after all, did he?
Oh boy. You are good at turning logic on it's head. War is peace. Love is hate. Unemployment is a stimulus. And now, limiting slavery creates second class citizens. I nominate you for the 2011 George Orwell Award.
Dude. Look up The Northwest Ordinance. Congress had regulated where slavery could be in the Territories from the very get-go.
Dude. The NWO was unconstitutional. Look up Article IV.
You might just also search through the old ACW threads for the place where you, Non-Sequitur, 4CJ, rustbucket, I think Pea Ridge, and one or two other people had a blazing gun-battle over the constitutionality of the NWO. I stayed out of it pretty much, iirc, because it was, well, "your issue", and I was pretty much a spectator. It was all entailed in a larger discussion of Dred Scott and the "personal liberty" laws of the Old Northwest States. (Illinois did have slavery for some time after statehood, since the French had introduced it in the 18th century iirc.) There was a big discussion about Illinois and their history of emancipation, and another about Pennsylvania and their partial, limited abolition which converted chattel slaves to indentured, and specified a term of indenture for slaves thus converted, in their bondage/modified abolition act.
I'll let you guys do the looking who are better at cruising old FR threads than I am (I'm on dialup and have not-so-hot search skillz).