The South lacked the finances, manpower, equipment, and industrial capacity to overpower the United States, let alone try and conquer South America or a part of it. The may have had a shot at some of the islands in the Caribbean.
I agree they did. But had they been able to expand they couldve grown into a strong nation and the union would be sandwiched between them and Canada with no growth potential.
That would have changed in less than a decade had they succeeded in maintaining independence. I think the border states would have eventually joined them. And then the territories. Eventually the CSA would be bigger and more powerful than the USA.
I think Lincoln and Northern businessmen could see this coming. I have said in the past, were I in Lincoln's shoes, I would have likely done the same thing. The South was an immediate economic threat, and over time would likely become a territorial threat.