I don’t really care that much for walls. My own preference would be an electrified fence, about 50’ high, razor wire of course, land mines for a quarter mile or so in front of the wall, and one of those six-barrel Dillon MGs about every quarter mile and sensors to detect/destroy anything trying to go over or under the wall.
That would work! Putting BP actually on Border would work too! Just saying.
Piranhas in the Rio Grande