After the War for Southern Independence, Confederate leaders acted on their view of a lush and productive empire. They would "civilize" the southern hemisphere, and bring a lawful and christian good to Latin America.
In late May, 1867, the CSA, striking from outposts and positions in Texas, Arizona, and California invaded the Empire of Mexico. This was the first territory the CSA would secure in the North-South American region. With decisive victories over the Mexicans, the CSA declared victory over Imperial Mexico. Using the same economic values as they did back in the mainland CSA, Mexico became dotted with massive slave based plantations. Of course, the CSA had a there work cut out for them after the annexation. The first priority was holding together the empire, as CS leaders did not want to then have to face down secessionist Mexican separatists. Although Mexico became a satellite of the CSA, they remained an Empire. President Hastings gave Maximillian I a position of secondary power as the Emperor, but he would answer to the President. And so the Empire of Mexico became the Confederate Empire of Mexico, and then, in 1887, the Imperial Mexican Confederacy.