OK, consider this an open TimeLine.
POD: 1833, the South Carolinan legislature convenes on March 11, 1833 and instead of repealing the Nullification Ordinance, it only digs deeper in it's state's rights doctrine.
Effects: The Civil War erupts, with President Jackson using his Force Bill to send Federal troops to South Carolina.
Here are the problems I'm having with these:
1. Why dous SC decide to keep the Nullification doctrine? Supposedly, John Calhoun was at a Congressional dinner and was rambling on about Nullification and how the south "would know what to do" when Jackson was forced to make a statement: he stood with his glass raised and said, "Our federal union, it must be preserved!" Calhoun backed down after that. Suppose either Jackson doesn't make such a comment, or it doesn't put Calhoun in his place?
2. How could South Carolina, after being firm in their position to stay to their Nullification, convince the other southern states to declare themselves independent? There's no way SC could fight an entire war by themselves, but perhaps combined with Georgia, Alabama, Mississippi, Louisiana, North Carolina, (and perhaps Virginia) they could win their independence as an earlier Confederacy.
3. Supposing that SC pulled the "way of life" card on the southern states, how would such a war fare for the south? As far as I can see, the North would have the upper hand in military commanders, Winfield Scott being the only one I know of. Can anybody think of any Southern commanders that could bring the south to victory? Maybe if SC brought Virginia to the Confederacy, then Scott would join the south... although the same event in OTL didn't yield that result.
4. I think it's safe to say Calhoun would've led the fight, at least politically for the Confederacy. Who would be in President Calhoun's cabinet? What would the Confederate government look like this early on?