For years I've been witnessing the debate of what mattered most to southerners in the 1800s, excessive taxes or an ability to own slaves. What first hand sources do you guys have to find out directly what justifications were used by South Carolinians to secede? I've also been told there were speech-givers that took SC's justification for secession and went touring in other states to help them decide to secede as well. Does anyone have any direct sources on this? What were they saying and why?
Definitely not asking for opinions so we can start a debate, just direct sources from southerners of the time.
Edit: The link is to a transcription of South Carolina's official declaration of secession posted online by Yale's law library. There is of course a whole lot more out there, but I'll leave both links to sources reflecting the broader discourse on secession, as well as their contextualization, to the experts.
Edit edit: Just wanted to offer an observation in regard to your query about the relative weight of slavery and taxation in prompting secession. The word 'tax' only appears once in the above text, and there in relation to the 3/5 compromise. The concern over the preservation of slavery suffuses the entire document.
I really wish the Lost Causer obfuscation around this question would disappear from Reddit and from the national discourse, but I'm not sure it ever will. That won't stop smart people at /r/AskHistorians from fighting the good fight, though. Check out the FAQ's relevant section here.