And so there you have it. The answer is 100%. But of course, many historians and college professors would have us believe that the South's use of Slaves was the real reason for the war and the North was just liberating them. Virtually all revenue in 1861 was derived from tariffs.
The fact is, those seven Southern States had already formed a new government with a new constitution and most importantly, a new tariff,which was about 10%. Unfortunately for the North, their tariff was about 40%. So if you were a ship owner bringing goods from England worth $100,000, you could arrive in Boston Harbor and and pay $40,000 in cash to unload your ship, filling the coffers of the U.S. Treasury, or you could arrive in Charleston Harbor and pay $10,000 in cash to unload your ship and fill the coffers of the C.S.A.
Given the choice between going home with $90,000 in his pocket or $60,000; no ship owner was going to bring one more dollar into a Northern Port.
As expressed in this article, there were great fears in the North that if Lincoln didn't act fast, money to operate the government including the army and navy would soon not exist.
So what do you think caused the war?