Instead have so many Sanctuary Cities, the United States government can create a new "Dreamer City" locating inside a less populated democratic state like New Mexico.
The undocumented immigrants should be separated from the regular populations to avoid crime and other racial-related problems. Most of the debates raised from those dreamers were "Keep Family Together". There are approximately 1.8 million dreamers out of the 11 million undocumented immigrants currently living in the United States. Why not gather the 1.8 millions and their associated family members, then reallocate them into a unique district, so they can fulfill their dreams as what Former President Obama had promised and also grant the Republicans by constructing the Trump border wall around "New Mexico City" at the same time.
Gambling business were/are legalized and localized in Las Vegas, NV and the surrounding cities. If people don't like slots and jackpots, don't go or live there.
If a Mexican American wants to be with his/her family, move to "New Mexico City".