Spain had it longer than Mexico did, with that only being a few decades. Wanna know how they lost it? They attacked us and started a war, which they lost. The territory that is now California was ceded to the US as part of the peace treaty. This was of course after US forces had captured Mexico City, meaning they got off easy with only being made to give up what they were.
No dip Sherlock, my point is that that’s not the same. The southern states of the confederacy succeeded, which in part resulted in the civil war. New Mexico was obtained from the Texas border dispute(Mexican-American war) and expanded with the Gadsden purchase. The historical context is different. And therefore your dumbass argument is a dumbass argument