Was not slavery already nationalized? It was how it would be accepted or not in what would become the newest states that caused the clamor.
There were some who were Southern who were also so wrapped up in their own system and interest that they hurt rather than helped. Had South Carolina been less aggressive at the beginning things may have been different. We can only guess at this point.
If there had been no large influx of Irish, German and other immigrants into the North, who would have done the work in the factories, railroads, mills and such? How would the North have replinished the work force if they had no steady stream? How would they have replinished their troops? Would it have been possible they could have run low on head counts too? As it was, there was a large number who seem to have been able to continue their way of life even with a war going on.
The Southern factions were split on so many issues but they came together when their soil was threatened and it was considered an invasion.
Pam