Just noodling here… POTUS now screaming for the wall (and other border securities). Smart enough to know that drone taxis (already a real thing) would quickly and easily transport people back and forth over a 30' wall.
https://www.npr.org/sections/thetwo-way/2016/06/08/481286099/drone-taxis-nevada-to-allow-testing-of-passenger-drone
He let's the "opposition" have their way, and no wall is built. Instead, they enforce the "never separate the children from their 'parents'" policy. EVERYONE that brings children across illegally are detained in adjoining cells; adult(s) in one, kids in the other. DNA tests are run and every time there is a mismatch, the children are either sent back (supervised) or detained until a proper solution found.
However, the child traffickers are already incarcerated! How many would have to hang from well-publicized gallows before NO ONE ever tries sneaking a kid into the USA?