jeffersondem well knows that slavery was important to all parties before, during and after the war.
Before the war Republicans were the first US political party to openly oppose slavery, to call it "wrong" and to demand restrictions on it.
Southern Democrats responded with increasing bitterness, threatening secession in 1856 if the abolitionist Republican won (he lost) and again in 1860.
Lincoln won and so Fire Eaters carried out their threats.
The Southern threats in 1856 and 1860 were not because of tariffs or "money flows from Europe", but because of Republicans' opposition to slavery.
And that's what Secessionists said in their Reasons for Secession documents.
In April 1861 war came, so who started it and why?
jeffersondem may agree with other Lost Causers who claim: Lincoln started war so he could collect tariffs from Charleston Harbor.
But Charleston produced less than 1% of US tariff revenues and the entire seceded Deep South only about 6%.
So the real question is: why did Jefferson Davis refuse to allow Lincoln to resupply Fort Sumter?
The answer to that is the real reason for Civil War.
Did it start over slavery?
No, but slavery immediately became a huge issue under terms like "Contraband of War" and the 1861 "Confiscation Ace", 1862 Emancipation Proclamation & Colored regiments, 1865 Abolition (13th), 1868 Citizenship (14th) and 1870 Voting Rights (15th).
Typical Civil War recruiting posters:
For this post, let's stipulate that you are correct: the war did not start over slavery.
We can forever dismiss the notion that the North fought for the high moral purpose of “freeing the slaves.”
But the North did fight. And for a very important reason. The North fought for what they considered their own best economic and political best self-interest.