I wasn't defending the North,
Nor am I defending the South - except insofar as I am defending the right of secession.
Otherwise, to hell with them. They were human-chattel slavers. 'Nuff said.
I'm just saying that slavery was the reason for secession and that is well documented.
Agreed 100%. I'm just saying that their "reasons for secession" and the "reasons for the war" are disjoint sets - or at least, their intersection does not include slavery.
Lincoln was perceived as an abolitionist in the South
Of course he was. A nice bit of useful propaganda, that - an easy way to rally & rile up the base (rather like interventionists conveniently "perceiving" Ron Paul as an "isolationist" ...)
But regardless of how he was perceived in the South, Lincoln was not, in fact, an abolitionist.
and the Republican Party was an abolitionist party.
The extent of their abolitionism appears to have been mostly restricted to a desire to prevent slavery from expanding into the western territories - a desire that largely seems to have been motivated not by any particular moral abhorrence of slavery, but rather to an eminently "practical" wish to prevent the bloc of slave states from gaining any more representation (and, hence, power) in the national legislature.
As a party, they were certainly not principled abolitionists (like William Lloyd Garrison). It is worth noting that the aforementioned "Corwin amendment" (which would have enshrined slavery
in perpetuo, as far as the federal government was concerned) was conceived, authored and proposed by Thomas Corwin - a Republican congressman from Ohio - and was, as mentioned, supported by newly-elected president Abraham Lincoln, who was also a Republican ...