We would straighten that out if it were annexed IMO.
You really think that the gang in DC and the gang in Mexico City could get together and smooth over Mexico's history of top down corruption and embrace of socialism, and organize a situation involving trillions of dollars in economic activity?
You have more faith in them than I do.
I believe such an arrangement would be the death of the American middle class, the end of our rule of law, and create a schism in cultures that would make the Balkans look pleasant.