The tariff laws were very unfair. But slavery was the 400 lb gorilla. It was a good rallying and recruiting tool for the North. The South was deathly afraid of a slavery revolt after what had happened in Haiti. They needed a military to keep order. That terrible war could have been prevented if the South had freed the slaves and the North had allowed the Army to keep the peace and prevent a slave rebellion. Fools on all sides particularly among those who would not be fighting.