California, Texas, New Mexico, Colorado, Arizona, Utah, Nevada, and Oregon - no matter how much of ‘Old Mexico’, or Azatlan, Mexico seizes, it will choke them to death.
Spain couldn’t even deal effectively with raiding Indians in those areas during the early 1800s. Mexico will continue to fail because they can’t admit failure is their fault - not the fault of the U.S.A.
The Spanish held Niles Michigan for a few days, I’m surprised they aren’t trying to claim everything between there and Mexico.