The most important thing to remember is that the war began over free trade capabilities. The north thought they had the almighty power to sanction and tariff southern colonies, who at the time were trading with Europe at more favorable pricing than the north could offer.
It was only after the war began, that Lincoln made the war's premise slavery, with the emancipation proclamation. Only by utilizing his newly implemented paper currency, and the noble cause of eliminating chattel slavery was Lincoln able to get the enlistment necessary to win a war for northern dominance.
Let it be remembered that Lincoln historically stated that if he didn't have to free the slaves, he wouldn't have.
Somehow government approved textbooks don't mention anything about the origins of the war.
