There’s a problem with your argument — the Southern states had viable Whig parties (except for SC) before the Civil War. In my state of TN, the Whigs were in the majority for a decent period. They effectively were formed in opposition to President Jackson. They could’ve continued (albeit only in the South) after the Civil War (a decade after the party ceased to be elsewhere), but were effectively absorbed into the Democrats since the GOP was deemed too radical (and anti-Southern) for them to enter into and have any influence. All the ideological battles from left to right were had within the Democrats in the South.
they had viable Whig parties but the Jeffersonian Democrats were utterly dominant.
Read the Confederate constitution some time. They gave the president a line item veto, forbade riders on bills to prevent pork barrel spending, required a balanced budget, required the central bureaucrats to answer to individual state legislatures, built in more explicit and stronger protections of the rights of states, required a supermajority to pass tax increases, etc etc. It would be an absolute dream constitution for Libertarians and Conservatives today in all those respects.
What this points to is how consistent Southerners have been in their political philosophy for over 200 years. If you read some of the letters people wrote back then or some of the newspaper editorials, you’ll be amazed how the views on many of these issues have not changed.
The Democrats today are the exact opposite on practically every single issue.