Conflating slavery with cotton production is absurd. Many slave states had little or no cotton production, but plenty of slaves. In the west, slaves could have been used in mining, as was done since antiquity. But if we accept that slavery could only be where cotton was grown, you'd have to include California, Arizona, Nevada, Kansas, Oklahoma, and New Mexico. So, basically the entire southwest to the Pacific.
Why do you think the confederate constitution went to such lengths to protect slavery in the territories they might acquire?
I have covered this before. Cotton cannot be grown in California, Arizona, Nevada, Oklahoma New Mexico and West Texas without irrigation systems that were not possible in the 19th century.
Cotton could have been grown in Kansas in very small quantities near the border with Oklahoma, but to no significant degree.
So as i've said, the claim that slavery was going to "expand" into the territories is actually an astro turf lie deliberately spread to prevent the Southern coalition from gaining any states that would upset the rigged game in Washington DC that kept the bulk of the profits from Southern production flowing through the hands of New York and Washington DC power brokers.
Why do you think the confederate constitution went to such lengths to protect slavery in the territories they might acquire?
As their constitution made it clear that slavery was protected throughout the Confederacy, your characterization of them protecting slavery specifically in territories they might acquire is deliberately misleading. There was no special consideration for territories.