Mexico, especially under Maximillian, would be in absolutely terrible condition, likely facing a protracted civil war and would in no way be able to offer effective resistance to an invasion. The Confederacy would win. They would land troops at Veracruz like the US had before and march on the capital. Napoleon won’t bother to help Mexico either, he had already drifted on to other things before Max was installed on the throne and didn’t even bother to help the poor guy IOTL.
Also I don’t see any way this could happen as the CSA and Mexican Empire would likely have amicable relations, and were very friendly during the civil war and I see expansionist ideals in the CSA being curtailed by international opinion against the possible spread of slavery.
Also I don’t see any way this could happen as the CSA and Mexican Empire would likely have amicable relations, and were very friendly during the civil war and I see expansionist ideals in the CSA being curtailed by international opinion against the possible spread of slavery.