It’s distressing that we even have to address this argument. It’s very difficult to go through, over or under a well-designed wall. If it’s long enough, it’s also very difficult to go around it, and therefore to get past it by any means, other than permission. If it’s very difficult to get past, then much fewer people will get in without permission. Mission accomplished. Is that so hard to grasp?
Any wall can be climbed or dug under if one has sufficient time and equipment. This does not mean a wall is not effective. They are very effective. Build the wall and monitor it with electronics and drones. When one trys to get over or under the wall send the border patrol to the area of attempted breach. This would take not a great number of border patrol agents. To defend the border without a wall takes tens of thousands of border patrol agents and many still get through.
How many prisoners have escaped over the walls of Leavenworth Prison? Damn few is the answer. I rest my case.
BUILD THE WALL!