the wall should be ‘protected’ with a WELL STOCKED moat, and a system to keep the wall greased and at an angle with an ‘eave’ over hang making it virtually impossible to scale it.
Of course, where there is a will, there is a way, which is why Drones and Warthogs would have to support the marksman on OUR side...
To be fair, those wanting to go BACK should be given a nice escort and XXX dollars PER PERSON, no hassle, just cash and a hearty handshake with a ‘good luck’ bouquet.
Razor wire works well on prison walls, so why not use it on the border wall? Sharp punji sticks pointing up from the ground on the U.S. side would help as well.
You've seen those electric zappers that kill flying pests? The wall should electrify those anti-climbing plates so when the illegal pests reach for it - "ZAP!", and they fall into your moat. Roasted meat for whatever you stock in the moat (crocs?).