More or less by accident I stumbled on this link from 2015 which must come from the mother-load of Lost Causer proof-texts.
To find them you have to page down about half-way, then you see posted 10 Lost Cause quotes that are frequently repeated on these threads.
They run from December 1860 through March 30, 1861 with a post-script from October 1862.
They constitute for Lost Causers "proof positive" that Civil War was not all-about slavery, but rather "raw power", "Northeastern power brokers" and "money flows from Europe".
So, first of all, please review my post #538 above which addresses one of those 10 quotes, about tariffs on railroad iron.
The fact is the fears expressed were misplaced and overblown.
The South consumed only 10% of total US iron, and could not possibly have re-exported to Union customers without paying Union tariffs.
Second, the "real reasons" for war in 1861 were the same as in 1776, 1812, 1846, 1898, 1917, 1941 & 2011 among other dates -- because Americans believed we'd been attacked, no deeper logic or explanations required.
As for why did President Lincoln send his resupply mission to Charleston in April 1861 -- to support President Buchanan's long-before promise not to surrender Fort Sumter without a fight.
Jefferson Davis' assault on Union troops there was a clear act of rebellion, and so Civil War was on.
Economics, "raw power", "money flows from Europe", etc., etc., can be interesting, but they don't explain Americans' response after Fort Sumter any more than they do in 1941 after Pearl Harbor -- regardless of how much Lost Causers hate to hear the truth of it.