[morphing libertarian]

cotton grows in California I think they still have fields in so cal, in Kern county.
California. California’s cotton is mostly grown in seven counties within the San Joaquin Valley, though Imperial Valley and Palo Verde Valley also have acres planted. In the 1990s cotton was also planted in the Sacramento Valley. California is the largest producer of Pima cotton in the United States.

Why do you associate expansion of slavery with growing cotton. Surely slaves can be put to other uses.

[DiogenesLamp]

California was already a "free" state, wasn't it? Apart from that, I am told that the cotton grown in California is grown because of irrigation pumps that carry the water and distribute it. They didn't have such a system in 1860. I'm thinking it was at least the 1920s before such stuff was developed.

I am also assured that everything in west Texas and further west, is only grown as a result of irrigation systems which did not exist, and would not exist for many decades into the future.

Why do you associate expansion of slavery with growing cotton. Surely slaves can be put to other uses.

Cotton was the primary cash crop using slaves. Why would you put them in the territories to make piddling amounts of money when they could make far more money in the cotton or tobacco fields? Bad investment.

If you look up the wikipedia entry on New Mexico territory, I believe it says there was 12 slaves in the entire territory, and that's when it extended all the way to California!