State's Right also includes the right to be and remain stupid. Slavery is a poor way to run an economy, as it does to people what no amount of money can fix.
It is my view point not to blame the Founders to much for their error in keeping slavery for what many thought was a while, and letting it die out on their own. In the 1780's that seemed a viable idea. Unfortunately, in 1793 Eli Whitney invented the Cotton Gin. To give an idea of how that changed things, in 1792, the South exported about a half million pounds of cotton, which seems huge to me. In 1793, with the cotton gin, they exported 100 million pounds. What was thought to be a dying system was unexpectedly revitalized. History is filled with unintended consequences.