First, the 100-ft Americas "Fences Make Good Neighbors" Friendship Wall.
Then, the US declares a year-long amnesty, said amnesty being Jose Paperloso has a year to vamoose back over the border.
Jose has the option of free transport to the border, where there are 500 pesos waiting for him.
If he and Mamacita Paperloso have anchor babies in tow, the bambinos are issued AmeriMex passports.
They can return to the US as full citizens at the age of 18. Any attempt to permanently resettle before that age would have to be Embassy-approved through the usual channels.
After one year, the amnesty expires, and Jose & Mamacita would be deported without recourse or renumeration, and their anchor babies stripped of any appeal to citizenship.