Nonsense, the war was about slavery in the south before it became about slavery in the north. It’s in the ordinances of secession for the various states of the CSA.
"The reductions were too little for South Carolina. In November 1832 the state called for a convention. By a vote of 136 to 26, the convention overwhelmingly adopted an ordinance of nullification drawn by Chancellor William Harper. It declared that the tariffs of both 1828 and 1832 were unconstitutional and unenforceable in South Carolina. While the Nullification Crisis would be resolved in early 1833, tariff policy would continue to be a national political issue between the Democratic Party and the newly emerged Whig Party for the next twenty years."
There is much revisionist history as in historical analysis that has confounded and confused many authors causing an ongoing debate. Lincoln would save the UNION at all costs...for about 3-4 years, the Southern States complained about unfair and unconstitutional tariffs levied on them by the Northern states causing South Carolina to withdraw from said UNION...what followed has been written and rewritten so that the UNCONSTITUTIONALITY has been lost and the more glamorous anti-slavery movement was used as the whip to stop a war weary UNION from quitting....emancipation was put into place, Secession by the South would not, could not be allowed....in this I agree but not by the bullheadedness of people in power to honor that CONSTITUTION. Here is history which come's closest to the truth if not the truth...I highly recommend both:
For Good and Evil: The Impact of Taxes on the Course of Civilization - When in the Course of Human Events: Arguing the Case for Southern Secession
... by the way the author, Charles Adams is a Northerner.