The slavery issue was astroturf for both sides. The Southern firebrands tried to use it as a wedge issue even though it clearly could not be abolished by anything the "free" states could do, and the "free" states tried to use it to keep the power of the congress confined to their side.
But the money streams don't lie. They tell the truth when all the people talking are trying to fool people as to their real motives.
The motives were always money. Money and power.
"...the mask has been thrown off and it is apparent that the people of the principal seceding states are now for commercial independence. They dream that the centres of traffic can be changed from Northern to Southern ports....by a revenue system verging on free trade...."Boston Transcript, March 18, 1861.
So let's first notice there was no such thing as "astroturf" in 1861, making the word not just false, but also inappropriate.
And who today ever even talks about alleged "astroturf"?
That's right, Democrats, like DiogenesLamp.
Second, there's no evidence suggesting the stated public reasons for secession were not the "real reasons" for 99%+ of Confederate voters.
If one percent shared DiogenesLamp's fantasies about a Confederate "free trade" empire, that in no way denies validity to the "real reasons" (i.e., slavery) why the 99% voted for secession & Confederacy.
DiogenesLamp: "The motives were always money. Money and power.
Only to Marxists, or to Lost Causers hoping to cast aspersions on normal Americans.
Second, in reality, there was nothing "free trade" about Confederate tariffs, that was just Democrat political hyperbole.
The original Confederate tariffs were simply the old relatively low Tariff of 1857 with some small modifications.
Their effect, barring some political accommodations, would be to double tariffs paid on any imports to either North or South which were later re-exported to the other.
Not good economically, but absent war a matter quickly settled by political accommodations.