California needs to outsource the holding of any non-citizen prisoners to their home countries. Pay Mexico a few dollars per day to host Mexican citizen prisoners, etc.
It would save a FORTUNE over paying American union wages to hold the same prisoners.
Or, alternatively, build the prison right there at the border with Mexico out in the desert. This would be a hard-times type prison, so it has plain food, no salsa, no corn tortillas, no meat ~ just beans, and corn fritters on Saturday.
There's a secure fence running many miles along the border from the South side of the prison. There's no way anyone can cross the fence.
There are NO LOCKS on the doors on the South side. In fact, the doors are always open, and as long as prisoners want to go out those doors they are free to do so.
Just inside the doors there are machinegun positions keeping out those who might try to enter the prison from Mexico. No matter how nasty a criminal might be he is able to just walk free by walking into Mexico just out the door!