1. By doing this you will cede the right to control immigration to the cities and states. It clearly is a Federal responsibility. If you cede control to the States, there will never be a chance of getting it under control.
2. If you let them flock to sanctuary cities in “red” or “purple” states, they will be immediately registered to vote and will vote Democrat. Remember Trump won PA, OH, WI and MI by very narrow margins. An influx of illegals who will be permitted to vote and who will vote Democrat will be enough to flip those states.
While it may be emotionally satisfying to see the sanctuary deal with the problem they created, it is not good for the country to let this happen
It’s got pluses and minuses. The Sanctuaries were winning the day, and expanding to ever more cities, large and small. The plus of sending criminaliens to them turned the tide of the dialog. Non-sanctuaries are thinking twice about becoming one. Sanctuaries are realizing maybe it’s not such a good idea.