Southern Rights did not cause the war but did cause the split in the Democratic Party in 1860. We didn't "rehash" this subject recently because a simple reading of Southern newspapers from 1860 is clear on this topic. Southerners repeatedly attacked Senator Stephen Douglas for his position on slavery in the territories - that people of a territory could vote to exclude slavery prior to slavery. Southerners called this "squatter's rights" as opposed to Southern Rights -- the ability of a slaveowner to take his slaves to a territory without having them declared free.
Long after the Civil War "States Rights" surfaced as a different issue which had to do with the power of the Federal government over the states. It couldn't have been important to Southerners in antebellum times because Southerners regarded the government in Washington as their ally and the Constitution as an ironclad protection for their rights to own slaves. The Supreme Court had ruled in favor of slaveholders in the Dred Scot Decision, and most American presidents up until Lincoln had supported the Southern position.
I really thought you would remember.
Okay, another question. Before Lincoln's election, what American president had been most hostile to Southern rights, but was arguably the most popular political figure to Southerners, as popular in antebellum times as FDR was to our parents?